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REESE. LIBRARY

UNIVERSITY OF CALIFORNIA.

TH E

QHEMICAL ANALYSIS OF IRON

A COMPLETE ACCOUNT OF ALL THE BEST
KNOWN METHODS

FOR THE

Analysis of Iron, Steel, Pig-iron, Iron Ore,

Limestone, Slag, CJay, Sand, Coal, Coke,

and Furnace and Producer Gases.

ANDREW ALEXANDER BLAIR,

Graduate United States Naval Academy, 1866; Chief Chemist United States Board appointed to

Test Iron, Steel, and other Metals, 1875 '•> Chief Chemist United States Geological Survey

and Tenth Census;. 1880; Member American Philosophical Society, etc.

THIRD EDITION.

"VX

0NIVERSITYJ
^

PHILADELPHIA:
B. LIPPINCOTT COMPANY.

1896.

TO MY WIFE,

WITHOUT WHOSE ASSISTANCE IT WOULD NEVER HAVE
BEEN WRITTEN,

THIS VOLUME

IS DEDICATED.

OF THE

•0NIVERSITT

TIVERSITT

PREFACE TO THE THIRD EDITION

SUCH changes as were necessary to bring the methods for
the determination of the various elements in accord with the
present state of the science have been made in this edition.

The method for the " Volumetric Determination of Phos-
phorus in Steel" is that worked out by the Sub-Committee on
Standards of the International Steel Standards Committee, and
as such is merely tentative. Its publication here is not official,
but through the courtesy of the committee it is placed before
the profession in the hope that criticism may confirm its value
or point out its errors. The modifications in the method for
the determination of sulphur in pig-iron are improvements, but
no method is perfectly satisfactory. Two new methods for the
determination of carbon are given, and some modifications of
Volhard's method for the determination of manganese in high
grade manganese ores are introduced.

Many minor changes have been made, and it is hoped that
this edition may meet the same cordial reception as the two
former.

LABORATORY OF BOOTH, GARRETT & BLAIR,
PHILADELPHIA, September, 1896.

PREFACE TO THE SECOND EDITION.

IN preparing the second edition of this book I have tried to
correct the mistakes that were apparent in the first edition, and to
add such matter as the advance in analytical chemistry seemed to
justify. In effecting the first of the objects I have been aided by
such kindly criticism as the profession and reviews offered me,
and in the second by the advice and assistance of many of my
fellow-workers. Among others my thanks are due to Messrs.
Maunsel White and A. L. Colby, of the Bethlehem Iron Company,
Mr. Clemens Jones, of the Thomas Iron Company, Mr. E. F.
Wood, of the Homestead Steel-Works, Mr. T. T. Morrell, of the
Cambria Iron Company, Mr. H. C. Babbitt, of the Wellman Steel
Company, Prof. F. W. Clarke, Chief Chemist U.S. Geological
Survey, Mr. J. E. Stead, of Middlesbo rough, England, and Mr. J.
Edward Whitfield, of Philadelphia.

It will be seen that the "Table of Atomic Weights" has been
revised ; the latest and most reliable values for the elements are
given, and the "Table of Factors" has been changed to corre-
spond to these values.

LABORATORY OF BOOTH, GARRETT & BLAIR,
PHILADELPHIA, June, 1891.

PREFACE TO THE FIRST EDITION

THE various methods for the analysis of iron and steel, as well
as the descriptions of special apparatus to facilitate the perform-
ance of the analytical work, are so widely distributed through
transactions of societies, journals, reviews, periodicals, and works
on general analytical chemistry, that only the possessor of a
chemical library can command the literature of the subject. It
is my object in the following pages to bring within the compass
of a single volume, as nearly as possible, all the methods of real
value to the iron analyst, and in doing this to give the credit of
originality for the different methods and improvements to the
proper persons. In many cases this has been very difficult, and
I shall be glad to have any mistake that I have made brought to
my attention.

This work presupposes some knowledge of general and
analytical chemistry, and some practical experience in laboratory
work and manipulation, as it is intended to be a guide for the
student of iron chemistry only. For such persons the details of
the descriptions of the methods will, I hope, often prove of great
assistance. With very few exceptions, these descriptions are the
results of my own experience in the use of the methods, and the
details are those that seemed to me to be of importance in their
practical performance. Many of the special forms of apparatus
are of my own contrivance ; they have proved extremely useful
to me, and I hope may facilitate in some cases the work of iron
chemists, to whom often very little is given and of whom very
much is required.

CONTENTS.

PAGE

APPARATUS II

APPARATUS FOR THE PREPARATION OF THE SAMPLES n

GENERAL LABORATORY APPARATUS 19

REAGENTS 37

ACIDS AND HALOGENS, 38. GASES, 42. ALKALIES AND ALKALINE SALTS, 44. SALTS
OF THE ALKALINE EARTHS, 50. METALS AND METALLIC SALTS, 52. REAGENTS
FOR DETERMINING PHOSPHORUS, 58.
METHODS FOR THE ANALYSIS OF PIG-IRON, BAR-IRON, AND STEEL . . 59

DETERMINATION OF SULPHUR. By evolution as H2S. Absorption by alkaline solution
of nitrate of 'lead ', 59. By ammoniacal solution of sulphate of cadmium, 62. By am-
moniacal solution of nitrate of silver, 62. Absorption and oxidation by bromine and
HCl, 63. Absorption and oxidation by permanganate of potassium, 64. Absorption
and oxidation by peroxide of hydrogen, 65. By oxidation and solution, 65. Special
precautions in the determination of S in pig-irons, 66. RAPID METHOD. Volumetric
determination by iodine, 68.

DETERMINATION OF SILICON, 72. By solution in HNO3 and HCl, 72. By solution in
HNO3 and H2SO4, 73. By volatilization in a current of chlorine gas, 73. RAPID
METHOD, 77.

DETERMINATION OF- SLAG AND OXIDES, 78. By solution in iodine, 79. By volatilization
in a current of chlorine gas, 80.

DETERMINATION OF PHOSPHORUS, 81. The acetate method, 81. When titanium is
present, 86. The molybdate method, 89. The combination method, 93. When
titanium is present, 94. RAPID METHODS, 95. Volumetric method, 95. Direct
weighing, 108.

DETERMINATION OF MANGANESE, 109. The acetate method, 109. General remarks on
the acetate method, 114. The HNO3 and KC1O3 method (Ford's), 115. Steel con-
taining much silicon, 117. Pig iron, 117. Spiegel and ferro-manganese, 1 18. RAPID
METHODS, 1 1 8. Volumetric methods. Volhard's method, 118. Williams' s method,
1 20. Deshays's method, 124. Pattinson's method (for Spiegel and ferro-manganese],
125. The color method (for steel), 126.

DETERMINATION OF CARBON, 129. TOTAL CARBON, 129. Direct combustion in a cur-
rent of oxygen, 131. Combustion with PbCrO4 and KC1O3, 132. Combustion with
CuO in a current of oxygen, 135. Combustion with Potassium Bisulphate, 135.
Solution and Oxidation in Sulphuric, Chromic, and Phosphoric Acids, the volume of
CO2 being measured, 136. Solution and Oxidation in Sulphuric, Chromic, and
Phosphoric Acids, the CO2 being weighed, 140. Volatilization of the iron in a cur-
rent of Cl, and subsequent combustion of the residue, 142. Volatilization of the
iron in a current of HCl gas, and subsequent combustion of the residue, 148. Solu-
tion in NH4C1, CuCl2, nitration, and weighing or combustion of the residue, 148.

10 CONTENTS.

PAGE

Solution in CuCl2 and KC1, filtration, and combustion of the residue, 161. Solution
in CuCh, and combustion of the residue, 162. Solution in I or Br, and combustion
with PbCrO4, or weighing, of the residue, 162. Solution by fused AgCl, and com-
bustion of the residue, 163. Solution of the iron in CuSO4, filtration, and combus-
tion of the residue in a current of oxygen, 163. Solution of the iron in CuSO4, and
oxidation of the residue by CrO3 -f- H2SO4, 164. Solution in dilute HC1 by the aid
of an electric current, and combustion of the residue, 165.

DETERMINATION OF GRAPHITIC CARBON 166

DETERMINATION OF COMBINED CARBON, 167. Indirect method, 167. Direct method

(color method), 167.
DETERMINATION OF TITANIUM, 178. By precipitation, 178. By volatilization, 180.

DETERMINATION OF COPPER 181

DETERMINATION OF NICKEL AND COBALT 184

DETERMINATION OF CHROMIUM AND ALUMINIUM, 187. Stead's method, 191. Carnot's
method, 192. Volumetric method for chromium, 193.

DETERMINATION OF ARSENIC 195

DETERMINATION OF ANTIMONY 196

DETERMINATION OF TIN 197

DETERMINATION OF TUNGSTEN 198

DETERMINATION OF VANADIUM 200

DETERMINATION OF NITROGEN 201

DETERMINATION OF IRON 204

METHODS FOR THE ANALYSIS OF IRON ORES 205

Remarks on sampling, 205. Determination of hygroscopic water, 206. Determination
of total iron, 207. Methods for standardizing the solutions, 218. Determination of
FeO, 223. Of S, 226. OfP2O5, 229. OfTiO2, 231. Of Mn, 233. Of SiO2, A12O3,
CaO, MgO, MnO, and BaO, 238. Of SiO2, 247. Separation of A12O3 and Fe2O3, 248.
Determination of NiO, CoO, ZnO, and MnO, 251. Of CuS, PbS, As2O6, and Sb2O4,
253. Of the alkalies, 255. Of CO2. 257. Of combined water and carbon in car-
bonaceous matter, 259. Of Cr2O3. 262. Of WO3, 264. Of V2O5, 264. Of sp. gr.,
265.

METHODS FOR THE ANALYSIS OF LIMESTONE 267

METHODS FOR THE ANALYSIS OF CLAY 271

METHODS FOR THE ANALYSIS OF SLAGS 276

METHODS FOR THE ANALYSIS OF FIRE-SANDS 281

METHODS FOR THE ANALYSIS OF COAL AND COKE 282

Proximate analysis, 282. Analysis of the ash, 283. Determination of sulphur, 284. De-
termination of phosphoric acid, 286.

METHODS FOR THE ANALYSIS OF GASES 288

Collecting samples, 288. Preparation of the reagents, 291. Analysis of the samples, 293.
Determination of CO2, 295. Of O, 296. Of CO, 296. Of H, 296. Of CH4, 298.
Example of calculation, 302.

TABLES 303

Table I. Atomic weights of the elements, 303. Table II. Table of factors, 304. Table
III. Percentages of P and P2O5 for each m.g. of Mg2P2O7, 306. Table IV. Tension
of aqueous vapor, 307. Table V. Table for reducing volumes of gases to the normal
state. 308.
INDEX 315

UNIVERSITY

^yfO^NlA^x

THE CHEMICAL ANALYSIS OF IRON

APPARATUS.

THE speed and facility with which results may be obtained, and often
the accuracy of these results, are dependent upon various mechanical
appliances as well as upon the skill of the analyst. These appliances will
be considered under separate heads.

APPARATUS FOR THE PREPARATION OF THE SAMPLES.

For crushing iron ores, a mortar and pestle, such as are ordinarily
used, have caused much trouble. In breaking up hard ores the wear,
especially on the pestle, is considerable, and the particles of cast iron may
cause the sample to yield too high a result in the determination of metallic
iron. Of course in non-magnetic ores these particles may be removed
with a magnet, but in the case of magnetic or partly magnetic ores this
cannot be done, and a hardened steel mortar and pestle should be used.
The sample should be broken to about pea size, well mixed, and quar-
tered, this quarter broken still finer, and mixed and quartered in the
same way until the resulting portion is small enough to be bottled. The
final grinding can be best made on a chilled-iron plate with a hardened
steel muller. Except with unusually refractory ores, further grinding is
unnecessary, but with such ores the final grinding must be in an agate
mortar. In large laboratories and where many ores are analyzed, arrange-

APPARATUS FOR THE PREPARATION OF THE SAMPLES.

ments such as are shown in the accompanying sketches will prove very
useful. Fig. I shows a steel mortar, the pestle worked by power, and
a chilled plate and muller. A is the mortar ; B, a wooden stem in which
the pestle fits. The cams H fit on the shaft and raise the pestle by
means of the tappets a, which are faced with raw hide. An iron hoop
shrunk on the mortar has a ring, in which is fastened the low^r block
of the pulley D ; the upper block is attached to a traveller, E. When in
use the mortar is covered with a leather cap, which prevents the pieces
of ore from flying out of the mortar. To transfer the powdered ore to

FIG. i.

the chilled plate F, remove the leather cap, raise the pestle clear of the
mortar, and fasten it up by a hook from the framework to the tappet a.
Raise the mortar by pulling the fall from the upper block and fastening
the hook in its end into a ring at the lower block. By means of the
traveller, run the mortar over the plate and turn the ore out. After
quartering the sample down, finish the grinding on the chilled plate with
the muller C. The sheet-iron troughs G serve to catch any ore that
falls from the plate. In some laboratories a small Blake crusher is used

AGATE MORTARS.

for crushing the ore, but it is more liable to get out of order, and is
not so easily cleaned as the mortar and pestle. Fig. 2 shows an arrange-
ment for facilitating the final grinding in the agate mortar, in which the
pestle is rotated by a Stow flexible shaft.

FIG. 2.

The apparatus shown in Fig. 3, designed by Mr. Maunsel White,
has been in use several years at the chemical laboratory of the Beth-
lehem Iron Company, and has worked very satisfactorily. The power is
applied from an overhead countershaft not shown in the cut. The lower
portion of the vertical shaft carries two horizontal pulleys, A and B;
these pulleys are connected, as shown, with the spindle carrying the
pestle and with the circular box D, in which the mortar is securely
fastened by four claw-bolts, which may be seen in the drawing.

The piece D is made with a spindle which extends down into a
bearing in the supporting piece H. The piece H, which may be called
a lever, is secured to the frame F by a bolt which passes through it,
and around which it can be turned through an angle sufficient to per-
mit of the easy emptying of the mortar without displacing the belt.

!4 APPARATUS FOR THE PREPARATION OF THE SAMPLES.

A groove at the farther end of H, as shown, carries a weighted rod which
supplies the pressure of the mortar against the pestle. The weights are
made movable so that the pressure can be varied for special cases.

FIG. 3.

The agate pestle is secured in a brass spindle with a grooved collar
for carrying the belt; this spindle revolves in a bored socket in the
piece E, and is secured from dropping out by means of a small nut,
shown at the top of the piece. The piece E is connected to the frame
F by a circular bolt, the end of which is supplied with an arm for
rocking the piece E; this obtains by fastening the bolt with dowel-pins
where it passes through the piece E while free to move in the frame
F. The pulley C is run from the countershaft, and revolves a small
shaft whose end carries a crank connected by a short rod to the bolt-
arm of the piece E, and supplies the power and means for the rocking
motion.

It will now be seen that while the mortar revolves, the pestle,
revolving more rapidly, sweeps across the face of the mortar by the

DRILLING-MA CHINES.

rocking motion of the piece E, thus constantly changing the material
between the grinding surfaces.

In taking samples of iron or steel, a perfectly clean dry drill should
be used, and the utmost care taken to prevent grease, oil, or dirt of any
kind from getting in the sample. With bar-iron or steel the scale on the

FIG. 4.

outside of the piece should be removed as carefully as possible, the first

drillings from each hole thrown away, and the remainder thoroughly mixed

and placed in a perfectly clean dry bottle. Fig. 4 shows a convenient

form of drill-press ^br the purpose. A half-inch Morse twist-drill is the

best for general use. In taking samples of pig-iron, the loose sand should

be carefully removed from the outside of the pig and a piece of stout

paper wrapped around it

to prevent the sand and FlG-

slag from the outside

getting mixed with the

clean drillings, which are

received on a piece of

glazed paper turned up

at the edges (Fig. 4).

Drillings from pig-iron

can be best mixed by

rubbing them up in a small porcelain mortar. At. blast-furnaces, to save

the trouble of breaking pieces from the pigs the arrangement shown in

APPARATUS FOR THE PREPARATION OF THE SAMPLES.

Fig. 5 is very convenient, as half a pig can be placed in the press. The
framework is securely bolted to the table on which the press stands, and
the pig is secured by means of the iron clamps. By removing the pieces
of wood under the pig it is lowered so that two or three holes can be
bored in different parts of the face of the pig to get an average. By
taking one pig from the first bed, one from the last, and one from an
intermediate bed, a good average of each cast may be obtained. When
the ore varies, or when mixtures of different ores are used, these pre-
cautions are very necessary to get a sample that will really represent an
average of the cast.

Drillings from large ingots must be taken by means of an ordinary
brace.

FIG. 6.

Fig. 6 shows an apparatus for the drilling and weighing of samples
of steel for colorimetric carbon or other rapid determinations, designed by
Mr. Maunsel White, and in use at the laboratory of the Bethlehem Iron

SPIEGEL MORTAR.

•7>X

Company. The drill is mounted above the balance, the point of the
drill directly overhanging the balance-pan. The piece to be drilled is
placed against the semicircular plate carried by the two rods that pass
through the drill-frame ; on the rear end of each rod is a coiled spring
which supplies the pressure necessary for drilling. The rear ends of the
rods are held together by a tie-piece, which is connected to a lever
operated by the foot, so that the rods and plate can be forced forward
for the reception of the piece to be drilled.

The balance is supplied with an overhead pan which receives the
drillings guided to it through the funnel fixed in the top of the balance-
case for this purpose. When the pan falls, showing that sufficient sample
has been drilled, pressure is applied to the lever by the foot and the
piece taken out. The balance-case rests upon an iron plate grooved on
the bottom ; these grooves engage with guides screwed to the table and
permit the balance-case to be pulled forward, which facilitates the cleaning
of the funnel from all clinging particles. This operation is done with a
camel-hair brush or a feather. A magnet is run around in the lower
pans to guard against the chance of
falling particles interfering with the
accuracy of the weights. The upper
door of the balance-case is then
lowered into the position shown in
Fig. 6, which gives free access to
the upper pan containing the sam-
ple. The sample is now accurately
weighed, the pan lifted out, and the
drillings transferred to the test-tube.

The use of a J^-inch twist-drill has
been adopted and found to give good
results. The pans and funnel are
aluminium and the bearings agate;
the beam is short, 5^ inches in length, in consequence of which the
weighing is done rapidly.

In taking samples of spiegel or of white-iron, small clean pieces from

FIG. 7.

jg APPARATUS FOR THE PREPARATION OF THE SAMPLES.

a number of pigs should be taken and powdered in a hardened steel
mortar. The mortar shown in the sketch (Fig. 7) is forged from high
carbon steel, hardened, and the temper drawn from the outside. This
makes the mortar both hard and tofrgh. The sheet-iron cover prevents
the pieces from flying. The face of the pestle is very hard, and the
handle comparatively soft, so that it will not break when struck by the
hammer.

In taking samples for analysis, when the method used requires the
sample to be in a fine state of subdivision, the very fine part of the
sample should never be separated from the coarser particles by a sieve or
screen, but the sample should be mixed thoroughly, and a portion, fine
and coarse together, taken and powdered, so that all may pass through
the sieve.

FIG. 8.

AIR-BA TH.

GENERAL LABORATORY APPARATUS.

Sand-Bath gmd Air-Bath.

Fig. 8 shows a very convenient form of sand-bath, and Fig. 9 an
air-bath. This air-bath is made from an ordinary cast-iron sink, which
is supported on fire-bricks. The top is of asbestos board, with a piece

FIG. 9.

of sheet-iron underneath to strengthen it. The holes are large enough
to take tho largest-sized beakers, while the smaller beakers are supported
by asbestos rings. An ordinary gas-regulator or governor, which supplies

GENERAL LABORATORY APPARATUS.

FIG. 10.

the gas at a constant pressure, keeps the temperature sufficiently uni-
form. Evaporations may thus be effected with great saving of time and
with little danger of loss by spirting. The products of combustion of
the gas are carried off by a separate flue, and the H2SO4 formed does
not come in contact with the solutions in the baths.

Instead of sand-bath the term hot plate is generally used for this piece
of apparatus, the surface of the iron being kept clean and free from
rust by an occasional coat of stove-polish. Evaporations on the hot
plate may be hastened by standing the beaker containing the solution
inside another beaker with the bottom cut off. Beakers may be readily

cut in this way by starting a crack and leading
it around with a red-hot iron or glass rod. For
evaporating solutions in capsules or dishes a
beaker cut off in this way and placed on a tripod
covered with wire gauze, as shown in Fig. 10,
may be used with great advantage. The cap-
sule is supported on an asbestos ring, A, the
bottom being about J^ inch (12 mm.) from the
wire gauze. A piece of thin asbestos board, B,
about y^ inch (18 mm.) in diameter, rests on
the gauze and covers the point of the flame of
the Bunsen burner, and, by throwing the heat
more on the sides of the capsule, tends to pre-
vent spirting when the solution in the capsule gets thick and pasty.

Apparatus for Hastening Evaporations.

The little piece of apparatus shown in Fig. II was designed by Mr.
]. E. Whitfield, and is most useful in hastening evaporations. It consists
of a platinum tube ^- of an inch in diameter, coiled above the burner
to present more heating surface, through which passes a blast of air.
As the platinum tube and Bunsen burner are both supported on the
arm of the stand, the level of the tube may be made to accommodate
itself to a crucible on a stand, to a capsule on a tripod (Fig. 10), or to

APPARATUS FOR HASTENING EVAPORATIONS.

a beaker on the air-bath. In the treatment of the insoluble residues
from ores by hydrofluoric and sulphuric acids it is quite invaluable, as
it not only hastens the evaporation but prevents loss by spirting.

FIG. ii.

The blast of hot air breaks the bubbles on the surface of the liquid,
and when properly directed it gives the liquid a rotary motion that
tends to throw onto the sides of the crucible any particles of the liquid
thrown up by the bubbles. The amount of heat that can be applied to
a crucible under these circumstances, without causing loss, is really
surprising. It is equally useful when evaporating solutions in beakers on
the air-bath or hot plate. In laboratories where a blast of air is always
at command, the principle may be applied in many ways (or hastening
evaporations

Even a cold blast of air from a drawn-out glass tube directed on
the surface of a liquid hastens the evaporation very materially.

GENERAL LABORATORY APPARATUS.

Igniting- Precipitates.

For ignitions, a Bunsen burner with a ring to regulate the supply
of air, provided with an ordinary glass chimney, as shown in Fig. 12,
is most convenient. By shutting off the air entirely a very low heat
may be obtained, which is not rendered variable by air-currents, and the
heat of the full flame of the burner is increased by the greater draft
caused by the chimney and the perfect steadiness of the flame. By using
a small platinum rod or wire to support the cover of the crucible, as
shown in Fig. 12, a gentle current is induced in the crucible, which, while
it greatly facilitates burning off carbon, is not sufficiently strong to cause
loss by carrying off even the lightest ash. The crucible may also be

FIG. 12.

FIG. 13.

FIG. 14.

inclined on its side, as in Fig. 13, the heat in this case being applied
near the top of the crucible. Fig. 14 shows an easy method of fitting
a chimney t;o a Bunsen burner by means of a cork and an ordinary
Argand chimney-holder. When a higher temperature than that obtain-
able by a Bunsen burner is required, a blast-lamp, worked by a foot-
bellows, by a water-blast, or by a small blower, is used.

FIL TER-PUMPS.

FIG. 15.

Tripods.

The most convenient arrangement for heating liquids in beakers,
flasks, etc., is the iron tripod (Fig. 15). It consists of a cast-iron ring
with three legs of heavy iron wire ^ inch
(6 mm.) in diameter. The ring is covered with
brass wire gauze, 40 meshes to the inch, which
can be replaced when it is burned out, but which
lasts a long time. The vertical height of the
tripod is about 7^ inches (191 mm.). A very
convenient form of burner is the Finkner ratchet-
burner, as the flame can be raised or lowered
by means of the ratchet on the burner, thus
avoiding the necessity of reaching back over the
table to the gas-cock. As the air and gas are both turned off at once,
there is less danger of the flame blowing out when it is turned very
low.

Filter-Pumps.

The use of filter-pumps for Bunsen's method of rapid filtration is now
very general, and greatly facilitates many operations. The kind of pump
is usually determined by the water-supply. With a good pressure of
water, the most convenient form of pump is the injector. Fig. 16 shows
the Richards' injector united with a blast-cylinder, by the use of which
a good air-pressure for use with the blast-lamp may be obtained. When
the pump is used for filtering strong solutions of HNO3 a glass injector
may be used, and the water allowed to flow at once into the sink or
waste-pipe. When the pressure of water is not great enough for an
injector the Bunsen pump may be used, the vacuum obtained of course
depending on the amount of fall. A tank with a ball-cock attachment
makes this form of pump most convenient.

An ordinary air-pump may also be used for many purposes, but of
course is unsuitable for filtering corrosive liquids, such as HNO3, unless a
wash-bottle containing a caustic alkali is interposed between the flask and

24 GENERAL LABORATORY APPARATUS.

the air-pump. The apparatus shown in Fig. 17 will give a very good idea
of an arrangement which is very convenient when a water-supply is not

FIG. 16.

available. The jug, which may be of three or five gallons capacity, serves
as a reservoir. It connects directly with the air-pump.

Bunsen's Method of Rapid Filtration.

This method is too widely known to make a detailed description neces-
sary, but some hints in regard to the details may be useful. In the first
place, it is very difficult to get good 60° funnels, so that the little perforated
cones of platinum to support the point of the filter, which are sold by chem-
ical dealers, rarely fit the funnel, and when they do not fit, the filters are

FILTERING APPARATUS.

apt to tear. The small funnel of platinum foil, as recommended by Bunsen,
can be made to fit the funnel better, but the edges sometimes cut the filter.

FIG. 17.

FIG. 18.

A small funnel of parchment pricked full of pin-holes, and of the size and
shape of the platinum-foil funnel, works very well. It
is a mistake to use too great a pressure, especially at
first, and the filter should be kept full. The filtering
flask should always be connected, not with the vacuum-
pipe directly, but with another flask fitted with a little
Bunsen valve, which allows the air to pass into the
vacuum-pipe, but, in case of a sudden stoppage in the
pump, prevents the back pressure from entering the filter-
ing-flask and blowing out the contents of the funnel.

Fig. 1 8 shows an arrangement for filtering into a
beaker instead of into a flask. It is necessary to have a
glass cover over the beaker, as shown in the sketch, on account of the ten-
dency the solution has to spatter, particles of the solution being carried out
of the beaker in the current of air flowing into the vacuum-pipe.

GENERAL LABORATORY APPARATUS.

Gooch's Method of Rapid Filtration.

The pierced crucible and cone, with asbestos felt, devised by Gooch,*
are almost indispensable to the iron analyst for the proper and rapid
execution of many operations, as will be seen by the frequent references to
them in the descriptions of the methods given farther on. Fig. 19 shows
the crucible and cap, and Fig. 20 the cone. The asbestos, which should be
of a soft, silky, flexible fibre, is scraped longitudinally (not cut) to a fine, soft
down, and purified by boiling in strong HC1, and washed thoroughly on the

FIG. 19.

FIG. 20.

FIG. 21.

cone. It may be dried and kept in a bottle. The perforated crucible is
placed in one end of a piece of soft rubber tubing, the other end of which
is stretched over the top of a funnel, as shown in Figs. 19 and 21. The
neck of the funnel passes through the stopper of a vacuum-flask. To pre-
pare the felt, pour a little of the prepared asbestos suspended in water into
the crucible and attach the pump. The asbestos at once assumes the con-
dition of a firm, compact layer, which is washed with ease under the pressure
of the pump. After washing the felt, suck it dry on the pump, remove the
crucible, detach any little pieces of fibre that may be on the outside of the
bottom of the crucible, slip on the little cap, dry, ignite, and weigh.
Remove the cap, place the crucible in the rubber holder, start the pump
and pour the liquid and precipitate to be filtered into the crucible, wash,
dry, ignite, if required, cool, and weigh as before. The cone is fitted to a
funnel by means of a rubber band stretched over the top of the funnel.

Proceedings Am. Acad. Arts and Sciences, 1878, p. 342; Chem. News, xxxvii. 181.

COUNTERPOISED FILTERS. 2j

The pressure of the pump pulls the cone down so that the overlapping part
of the band forms a tight joint between the cone and the upper part of the
funnel (Fig. 22). The felt is prepared in the same manner as in the crucible.

Fill the cone with the asbestos suspended in water,

FIG. 22.
start the pump, press down the cone into the funnel,

and, if necessary, pour in more of the asbestos, letting
it run all around from the upper edge of the cone so
as to fill all the holes and make a firm, cohesive layer
all over the inside of the perforated portion of the
cone. Wash it well with water and suck it dry. It
will then be ready for use. The cone is not intended
for use when the precipitate is to be weighed, but, as it
presents a very large filtering surface, it is most useful for such precipitates
as MnO2 precipitated by Ford's method, etc. In this case, when the precipi-
tate has been washed and sucked dry, by removing the cone from the funnel
and carefully separating the felt from the sides of the cone with a little piece
of flattened platinum wire, it may be removed from the cone with the pre-
cipitate enclosed in it, and the whole mass transferred to a beaker or flask
for resolution. The cones may be of various sizes ; for ordinary use, a cone
1 2^ inches (45 mm.) in diameter is very convenient. They may also be
used with a paper filter. In both the crucibles and cones the holes should
be very small, and drilled (not punched) as closely together as possible.

Counterpoised Filters.

The Gooch crucible and felt are most useful for weighing precipitates
which are to be dried and not ignited, as in the direct weighing of the
phospho-molybdate of ammonium. When they are not available, however,
recourse must be had to counterpoised filters. The best method for
preparing and using them is as follows : Take two washed filters of the
same size and about the same thickness, fold them as if about to fit
them in funnels, and, by cutting from the upper edge of the heavier of
the two with a pair of scissors, make them nearly balance. Place them
between a pair of watch-glasses, as shown in Fig. 23, dry them at 100°
C, and allow them to cool in a desiccator. Place one in each pan of

LIBRA?.

OF THE

28 GENERAL LABORATORY APPARATUS.

the balance, and, handling them with a pair of forceps, clip them until
they balance exactly. Place each filter in a funnel, filter the precipitate
Fl on one of them, pass the clear filtrate (not the

washings) through the other, and wash them both
in the same manner. Remove them from the
funnels, turning over the top edges of the filter
containing the precipitate to prevent any of the
latter from falling out, place them in a watch-
glass, dry them at 1 00° C. (or at the required temperature, whatever it
may be), cover them with the other watch-glass, cool in a desiccator,
place them on opposite pans of the balance, and the weight added to
the pan containing the empty filter, to make them balance, is the weight
of the precipitate.

Filter-Paper.

All filter-paper contains more or less inorganic matter, which remains,
after burning the paper, as a white or brownish ash. The Swedish
paper with the water-mark J. H. Munktell leaves the smallest amount
of ash, and this ash contains from 35 to 65 per cent, silica, besides
ferric oxide, alumina, lime, and magnesia in varying proportions.

Schleicher & Schull prepare some very pure filters by washing them
with HC1 and HF1, and these should always be used for very accurate
work unless the analyst prepares ashless papers for himself. The com-
moner kinds of German paper contain much larger amounts of inorganic
matter than the Swedish paper, and it usually consists principally of
carbonate of calcium, but sometimes contains appreciable amounts of
phosphates.

Filters of this kind should always be washed with HC1 before they
are used. They may be washed by fitting them in a funnel, pouring on
hot HC1 and water (i part acid to 3 parts water), and washing thoroughly
with hot water. They may also be washed in the apparatus shown in
Fig. 24. It consists of a bottle of the proper size with the bottom cut
off with a hot iron. It contains a disk of wood cut to fit the shape of
the bottle and perforated with a number of gimlet-holes. Fill the bottle
half full of cut filters, pour on a mixture of HC1 and water (1-3), allow

APPARATUS FOR WASHING FILTERS.

them to stand about half an hour, and wash thoroughly with distilled water.
The bottle may be attached to the vacuum-pump and washed under
pressure. Dry the filters at a temperature below 100° C. For prepar-
ing ashless filters the apparatus shown in Fig. 25 is used. It is of spun
copper, lined with platinum throughout. Over the vertical tube is a
perforated platinum disk countersunk to the level of the bottom of the

FIG. 24.

FIG. 25.

dish. It is attached to the pump, and the filters are washed first with
HC1 and water (1-3), then with water to remove the lime, then with
HF1 and water (1-3) to dissolve the silica, and finally with distilled
water. Swedish filters washed in this way are practically ashless, the ash
from five filters, each 3 inches (75 mm.) in diameter, weighing less than
-j1^ mg. Filters may be cut out, using tin disks of the proper diameter as
patterns ; they may be bought ready cut, or they can be cut out at shops
where circular labels are cut at very small cost. The best way is to buy
Swedish paper and a good tough German paper, by the ream, have the
paper cut into filters of the proper sizes, say 5^ inches (140 mm.), 4}^
inches (108 mm.), and 3 inches (76 mm.) in diameter, and wash the Swedish
with HC1 and HF1 and the German with HC1. The ashless filters can

GENERAL LABORATORY APPARATUS.

be used for final filtrations when the precipitate is to be ignited and
weighed, and the German for all other work.

Washing-Bottles.

Figs. 26, 27, and 28 represent different forms of washing-bottles.
For ordinary use that represented in Fig. 26 is the best. The neck
is wrapped with thin asbestos board, covered with a piece of wash-
leather or chamois, which is sewed to keep it from slipping. This is
very necessary when hot water is used. A piece of soft rubber tubing
at A is more pleasant for the mouth than the glass, and after com-
pressing the air in the flask the tube can be grasped with the teeth,
thus keeping up the stream of water for some time without effort. It
FIG. 26.

FIG. 27.

FIG. 28.

also prevents the lips from being scalded when using very hot water.
Fig. 27 shows a movable tip, which allows the stream of water to be
directed by means of the finger. The form of flask shown in Fig. 27
is very convenient to use with ammonia-water, etc. The tube a is
closed with the index finger, while the Bunsen valve b closing as soon
as the air is compressed in the flask prevents the vapors from coming
back into the mouth, and the stream of liquid is stopped instantly by
removing the finger from a. Fig. 28 shows the Berzelius form, which
is sometimes very useful. The air is compressed by blowing into the
bottle through the jet, and by quickly inverting the bottle the stream

MEASURING- GLASSES.

of liquid is forced out until the equilibrium is restored. It requires
a little practice to use this form of bottle easily, but when the art is
once acquired it can be used with ammonia-water as well as pure water,
and the facility with which it can be moved and pointed in any direction
with the hand makes it most convenient for some purposes.

Removing Precipitates from Beakers.

A feather trimmed in the way shown in Fig. 29 may be used to
remove particles of adhering precipitates from beakers, evaporating-dishes,
etc. A piece of soft rubber tubing on the end of a piece of glass rod
or sealed glass tube is much more effective and convenient in most cases.

FIG. 31.

FIG. 29.

FIG. 30.

It is made by taking a short length of rubber tubing, placing a little
pure caoutchouc dissolved in chloroform or naphtha in one end, squeezing
the sides together between two pieces of board (Fig. 31), and allowing it
to remain for at least twenty-four hours. It may then be trimmed down
and placed on the end of a piece of glass rod or on the end of a piece
of glass tubing having the ends fused together (Fig. 30). This little instru-
ment has acquired the name of " policeman."

Measuring-Glasses.

In adding reagents to a sample or to a solution, measured amounts
should nearly always be used, and, as it is generally well under
all circumstances to avoid adding them from the bottle direct,
little beakers of the form shown in Fig. 32 are very useful.
They can be graduated and marked by covering the side with
a thin coating of paraffine, measuring in water from a burette,
marking the levels and amounts in the paraffine with a sharp-
pointed instrument, and etching them in the glass by filling the marks

FIG. 32.

3 2 GENERA L LAB OR A TORY A PPA RA TUS.

with HF1. After standing a few minutes the HF1 may be washed off
under the hydrant and the paraffine removed with hot water. As the
amounts are intended to be only approximate, no great degree of care
need be exercised in the graduation.

Caps for Reagent-Bottles.

The stoppers and lips of reagent-bottles are very apt to become
covered with chloride of ammonium, dust, etc., when exposed in the
laboratory, and especially such as are not in constant use, volumetric
solutions, stock-bottles, etc. It is well to keep them always covered with
caps, which may be bought from the dealers, or with cracked beakers,
which answer the purpose nearly as well in most cases.

Rubber Stoppers.

Rubber stoppers are now generally used instead of cork. Solid
stoppers should always be purchased, and the holes cut with the ordinary
cork-borers. This is readily done by moistening the cork-borer with
water or alcohol. A little practice will enable any one to do this with
great ease.

Desiccators.

Crucibles should always be cooled before weighing in desiccators.

The form shown in Fig. 33 is most convenient. The
FIG. 33.

desiccator should contain fused chloride of calcium.
The crucible rests on a small triangle, which may
be made of copper wire, each side being covered
by winding a thin strip of platinum foil around it
to prevent the crucible from coming in contact with
the copper, which may become more or less cor-
roded.

PLATINUM APPARATUS.

Crucibles.

The shape of the crucible is of considerable importance as regards
its wearing properties. Fig. 34 shows the best form for general use.

PLATINUM CRUCIBLES. 33

A crucible \y2 inches (38 mm.) high, i^- inches (33^ mm.) wide at
the top, with a capacity of 20 c.c., and weighing with the lid about 25
grammes, is well adapted for weighing the usual precipi- F|G

tates found in the course of iron analysis. For fusions a
much larger crucible is necessary: one i-ff inches (46
mm.) high, i-J-| inches (46 mm.) wide on top, with a capa-
city of 55 cc., and weighing about 60 grammes, will be
found convenient and serviceable. Pure platinum is the
best metal for crucibles. The iridium alloy, at one time so popular, has
not been found to wear well. It is stiffer than the pure metal, but much
more liable to crack. The endurance of a crucible depends very much
upon the treatment it receives. The salts of easily reduced metals fusing
at a low temperature, such as lead, tin, bismuth, antimony, etc., should
never be ignited in platinum ; besides these, the phosphoric acid in some
phosphates is occasionally partly reduced, rendering the platinum very
brittle. A platinum crucible should never be bent out of shape when
it can be avoided, and a wooden plug exactly the shape of the crucible
(Fig. 35) is very useful to straighten it on when it has been bent. It
should always be carefully cleaned before use : the precipitate FlQ
last ignited should be dissolved in acid if possible, and the
crucible washed out with water, dried, ignited, and cooled in
a desiccator before weighing. A precipitate of Fe2O3 will
sometimes stain a crucible very badly ; this stain may be
removed by allowing the crucible to stand with cold HC1
for twelve hours, and then warming it for a short time.
Stains that are not removed by HC1 may be removed by
fusing KHSO4 in the crucible, or by fusing Na2CO3 in it, dissolving in
water, and then treating the crucible with HC1. Whenever a crucible
begins to look dull and tarnished it should be cleaned inside and out
with very fine sea-sand (not sharp sand) by moistening the finger, dip-
ping it in the sand, and rubbing the crucible with it. This method of
cleaning decreases the weight of the crucible very slightly, the sea-sand
burnishing without cutting the crucible. It is very convenient to have
each crucible and its cover marked with a number, as shown in Fig. 34.

34 GENERAL LABORATORY APPARATUS.

Dishes.

Fig. 36 shows a very convenient form of dish for the determination of Si
in pig-iron, SiO2 in iron ores, etc. It is 3^ inches (83 mm.) in diameter

and 21/ inches (57 mm.) high.
FIG. 37.

Fig. 37, for such work as precipi-
tation of Fe2O3, etc. It is 5 inches
(127 mm.) in diameter and 3T5g-
inches (84 mm.) high. The wire
which is fused into the top of the
dish makes it much stiffer than it
would otherwise be, and consequently it may be made lighter and cheaper
than would be possible without the wire. The wire is hammered out and
helps to form the lip. A platinum stirring-rod, formed from a piece of
seamless tubing, rounded and fused together at the ends, is useful for
many purposes. It may be from 5/^ to 7 inches (140 to 179 mm.) long,
y^ inch (6 mm.) in diameter, weighing from 7.5 to n grammes.

Spatula.

Fig. 38 shows a very convenient and useful form of spatula. The

blade, which is made of the platinum-iridium alloy,

is fused into a tube of the same alloy which forms

— ^~ the handle. The weight of the spatula shown in

the sketch is 14 grammes, length 6^4 inches (165 mm.).

Triangles and Tripods.

The triangles for supporting the crucibles during the ignition are
shown in Figs. 12 and 13, as are also tripods for holding the lids, etc.
These are made from wire about -^ inch (1.6 mm.) diameter, the ends
are fused, and the wire, where it is twisted, has the parts in contact
fused together almost to the inside of the triangle, which makes it much
stiffer. The triangles should be attached to the iron rings of the sup-
ports with a few turns of fine platinum wire.

BALANCES.

Crucible-Tongs.

Fig. 39 shows the best form of crucible-tongs. The part from a to b is
of platinum, the straight part from a to c fitting over the end of the iron.
The surfaces at d are in contact when the tongs are closed, and with this
portion the lid can be handled, and the crucible is clasped by the curved
ends, which hold it firmly without any danger of bending the crucible.

FIG. 40.

They are especially useful in handling a crucible containing a liquid fusion.
Another form, shown in Fig. 40, is generally of brass, the points and bend
being lined with platinum. A small pair of forceps (Fig. 41) is useful for
taking the crucible from the desiccator and placing it on the balance, the
lid of the crucible being slipped a little to one side to allow one of the
points of the forceps to go inside the crucible.

Balances.

The balance is one of the most important things in the equipment of
a laboratory, and a cheap balance is nearly always a very poor investment.
The quality of balances has improved greatly in the last few years, and
it is now possible to get a most admirable instrument of this kind at a
comparatively low price. Fig. 42 shows a balance which for sensitiveness
and quickness is unsurpassed. It is made to carry up to 200 grammes in
each pan. The beam is of aluminium, as are also the pans. The stirrups
are of nickel, the knife-edges and bearings of agate, while the arrangement
for carrying the riders (Fig. 43) is most ingenious and effective. It is of
course very convenient to have one balance for weighing crucibles, etc., and
another for weighing samples for analysis. The balance for the latter pur-
pose may be much smaller than the balance for the former, and should be

GENERAL LABORATORY APPARATUS.
FIG. 42.

(D jTol

^aa^

provided with a small aluminium pan with a spout (Fig. 44), to facilitate
T- the transfer of samples to

r IG. 43*

flasks, test-tubes, etc. This
pan should have a coun-
terpoise. A pair of small
forceps, slightly magnetized,
may be used to advantage

Fie;. 44-

in getting exact weights of steel drillings, and a camel's-hair brush is
necessary to detach small particles of ores, etc., from the aluminium pan
or balanced watch-glasses.

DISTILLED WATER.

Factor- Weights.

The use of factor weights is in many cases extremely convenient, as
it does away with all calculation, and is to that extent time-saving and
valuable in avoiding one source of error. Thus, in determining carbon by
combustion in steel, using 2.7273 grammes of the steel, o.i milligramme
of carbonic acid is equal to o.ooi per cent, of carbon in the steel. For
determining silicon in pig-iron the ^ factor weight, or 1.1755 grammes, is
very convenient. When the weight of SiO2 is multiplied by 4, one milli-
gramme is equal to o.oi per cent, of silicon. Or, for rapid silicon deter-
minations, the Y1^ factor weight, 0.4702 gramme, is used.

REAQBNTS.

Distilled Water.

When only a small amount of distilled water is needed, a tin-lined
copper still and condenser, such as are furnished by all dealers, may be

FIG. 45.

2 8 REAGENTS.

used, but where there is a supply of steam, an arrangement like that
shown in Fig. 45 will be found most useful. A is a tin-lined copper
cylinder, with a dome-shaped top, E, fitted to A by the joint shown in
the sketch, which may be made tight by paper or a linen rag. Two
perforated shelves, a, a, support layers of clean quartz-gravel or pieces of
block-tin, which wash the steam and prevent dirt from being carried over
mechanically. The steam enters at B, and the water condensed in the
cylinder A passes off through the pipe C. The washed steam passes
up through the block-tin pipe G, and is condensed in the worm-tub F.
A glass worm should never be used, as the water condensed in it dis-
solves notable amounts of elass.

ACIDS AND HALOGENS.
Hydrochloric Acid. HC1. Sp. gr. 1.2.

Chemically pure hydrochloric acid is readily obtained. It should be
free from chlorine, sulphuric and sulphurous acid, arsenic, and fixed salts.
To test for sulphuric and sulphurous acid, evaporate 100 c.c. to dryness
with a little pure nitrate of potassium, redissolve in water with a few
drops of HC1, filter, if necessary, and add chloride of barium. To test
for arsenic, put into a clean dry test-tube a few centigrammes of pure
stannous chloride, pour in carefully 6 or 8 c.c. HC1, and gradually 2 or
3 c.c. pure H2SO4, shaking the test-tube gently. If the HC1 is free
from arsenic the solution remains clear and colorless, but if arsenic is
present the solution becomes yellowish, then brownish, and finally
metallic arsenic is deposited. The test-tube should be gently warmed if
no reaction occurs at first. To test for chlorine, pour some of the acid
into a solution of iodide of potassium containing a little starch solution.
A blue coloration indicates chlorine or ferric chloride. To test for
metallic salts, neutralize about 100 c.c. of the acid with ammonia and
add sulphide of ammonium. To test for salts of the alkalies, evaporate
about TOO c.c. of the acid to dryness, and test any residue which may
remain.

HYDROFLUORIC ACID.

Nitric Acid. HNO3. Sp. gr. 1.41.

Nitric acid should be free from nitrous acid, the presence of which
may be known by the yellowish color it produces. It may be freed
from this gas by passing a current of air through the acid until it
becomes colorless. To test for HC1 or Cl, dilute largely and add a
solution of nitrate of silver. To test for fixed salts, evaporate about
100 c.c. to dryness. The ordinary acid diluted with an equal volume of
water gives the acid of 1.2 sp. gr. used to dissolve steel for the color
carbon test. It should be carefully tested for Cl or HC1.

Sulphuric Acid. H2SO4. Sp. gr. 1.84.

Sulphuric acid should be colorless. To test for oxides of nitrogen,
Warington* suggests placing about two pounds of the acid in a bottle,
which it half fills, and shaking violently. The air washes the gases out
of the acid, and the presence of the oxides of nitrogen may be detected
by placing in the mouth of the bottle a piece of filter-paper saturated
with iodide of potassium and starch solution, which is colored blue when
any of these oxides are present. To test for lead, supersaturate some
of the acid with ammonia and add sulphide of ammonium.

« Hydrofluoric Acid.
The use of Ceresine bottles,
suggested by Prof. Edward
Hart, of Lafayette College, has
made it quite possible to ob-
tain pure hydrofluoric acid,
but the crude acid may be
redistilled in the laboratory
into platinum bottles. The
crude acid, which may be pur-
chased from glass engravers
and etchers, is distilled from
a platinum, silver, or lead still, as shown in Fig. 46. The head of the still

Crookes's Select Methods, 2d ed., p. 494.

40 REAGEN'IS.

and condensing-tube is of platinum. The condensing-tube runs through
a copper box filled with ice, and a platinum bottle receives the condensed
acid. Where the tube comes through the lower part of the box it is
secured by a rubber stopper, and a small bit of paper around the tube
prevents any condensed moisture on the outside of the tube from running
into the bottle. Before distilling the acid, put into it a few crystals of
permanganate of potassium and a few c.c. of H2SO4. The redistilled acid
should leave no residue upon evaporation.

Acetic Acid. H,C2H3O2. Sp. gr. 1.04.

Acetic acid of the strength given above is the best for use in iron analy-
sis. It should give no residue on evaporation, and no precipitate upon neu-
tralization with ammonia and the addition of sulphide of ammonium. It
should be free from phosphoric acid. To test it for phosphoric acid, evapo-
rate 100 c.c. nearly to dryness, add a little magnesium mixture and a large
excess of ammonia, cool in ice-water, and stir vigorously. When phos-
phoric acid is present, a precipitate of ammonium magnesium phosphate
will be obtained.

Citric Acid. H3,C6H5O7,H2O.

Citric acid is easily obtained in a state of purity in the form of crys-
tals having the above composition. It should be kept in the solid condi-
tion, and dissolved as needed. It is soluble in ^ part of water at 15° C.

Tartaric Acid. H2,C4H4O6.

Tartaric acid is also easily obtained sufficiently pure for use in iron
analysis. The crystals should be dissolved only as needed. The only
impurity is a small amount of lime. It is soluble in y2 part of water at
15° C.

Oxalic Acid. H2,C2O4.

Oxalic acid crystallizes from its aqueous solution as H2,C2O4,2H2O,
soluble in 8.7 parts of water at 15° C. It loses its water of hydration very
easily even at the ordinary temperature in dry air, and very quickly at
100° C.

ACIDS. ,[

Bromine. Br.

Bromine is easily obtained in a condition sufficiently pure for use as
a reagent. It is a dark brown, extremely corrosive liquid, of sp. gr. 2.97.
It is soluble in about 30 parts of water at 15° C. It is best kept in a
glass-stoppered bottle with a ground cap. As the aqueous solution is
generally used, it is convenient to put only a small amount, say 20 or 30
c.c., in the bottle, fill the bottle nearly full of cold distilled water, shake it
up well, and pour off the saturated solution as required. There usually
remains in the bottom of the bottle a small amount of impurity, which
is insoluble in water.

Iodine. I.

Iodine is a metallic-looking crystalline solid, of sp. gr. 4.95. Resub-
limed iodine is not sufficiently pure for use, and must be redistilled with
great care, unless it is used as iodine dissolved in iodide of iron, and
filtered. To distil it, place about y2 kilo, in a large glass retort of about
2 litres capacity connected with an adapter about 1 8 inches (456 mm.) long
and 3 inches (75 mm.) in diameter at the largest part. The heat from
a Bunsen burner turned quite low will cause the violet vapors of iodine
to pass rapidly into the adapter, where they will condense without any
means being taken to cool it. By gently warming the outside of the
adapter after the distillation has been finished, the iodine may readily be
detached in large masses and removed. It should be kept in a wide-
mouth, glass-stoppered bottle.

Chlorine. Cl.

Chlorine is a yellowish gas about two and one-half times heavier than
air. It is sparingly soluble in water. When required it must be made.
The details are given under " Determination of Silicon in Iron and Steel."

Sulphurous Acid.

To make sulphurous acid gas, mix powdered charcoal and strong
sulphuric acid until a thin paste is formed, heat the paste in a flask,

42 REAGENTS.

very gently at first, and pass the gas through a washing-bottle containing
a little water. The reaction is C+ 2H2SO4 = CO2+ 2SO2+ 2H2O. The
tube leading from the flask into the washing-bottle should have a bulb
in it to prevent the reflux of water into the flask in case of sudden
cooling. Clippings of sheet copper, or copper turnings, may be used
instead of charcoal, and are generally to be preferred. The best propor-
tion is 250 grammes of copper to 500 c.c. of strong sulphuric acid. The
aqueous solution of the gas is made by passing the washed gas into dis-
tilled water. The gas, SO2, has a specific gravity of 2.21 (air = i.). i c.c.
of water at 15° C. dissolves 0.1353 gramme of SO2.

Chromic Acid. CrO3.

Chromic anhydride as a red powder or in the form of scarlet crystals
is easily obtained in a state of purity. It is deliquescent, and dissolves
in a small quantity of water, forming a dark brownish-colored liquid. It
may be made by pouring i volume of a saturated solution of bichromate
of potassium into \y2 volumes of strong sulphuric acid, stirring con-
stantly. The liquid on cooling deposits needles of chromic anhydride,
which must be separated from the mother-liquid and purified by re-
crystallization.

GASES.

Carbonic Acid Gas. CO2.

The best form of generator is shown in Fig. 47. It was first sug-
gested by Casamajor.* It consists of a large tubulated bottle, the bottom
of which is covered to the depth of about I inch (25 mm.) with buck-
shot, on top of which rest lumps of marble. Dilute hydrochloric acid
(i acid to 5 water) is admitted through the tube which enters at the
tubulure at the bottom of the bottle, bending down so as to reach the
bottom of the bottle. The wash-bottle A contains water. By blowing
in the rubber tube attached to the acid-bottle the acid passes over into
the tubulated bottle. When the stopcock K is closed, the pressure in

* American Chemist, vi. 209

GASES. 43

the tubulated bottle forces the acid back into the acid-bottle. When the
acid becomes exhausted and remains in the tubulated bottle, pour a
little strong HC1 into the acid-bottle and blow it over into the tubulated
bottle. The generated gas will force the liquid back into the acid-bottle,
when it can be replaced by fresh acid. A slightly different form is
shown in Fig. 50.

Sulphuretted Hydrogen Gas. H2S.

The same form of apparatus is used for generating H2S. Ferrous
sulphide is substituted for marble, but HC1 is used instead of H2SO4, as
is generally advised, for the ferrous sulphate formed crystallizes out and
clogs the apparatus.

Hydrogen. H.

The same form of apparatus as that used for CO2 and H2S can be
used to advantage for generating hydrogen gas. Pieces of zinc, which
may be obtained by melting the zinc and pouring it in a sheet about
y^ inch (6 mm.) thick, so that it can be easily broken, are to be used,
and not granulated zinc. Hydrochloric acid is better than sulphuric.

Oxygen Gas. O.

Oxygen compressed in cylinders can be obtained from most dealers
in chemicals, but it should always be carefully tested before being used
for the determination of carbon in steel or iron, as the cylinders are
sometimes filled with coal-gas, and a cylinder which has once held coal-
gas is rarely free from hydrocarbons.

The gas may be made on a small scale in the laboratory by care-
fully mixing in a porcelain mortar 100 grammes chlorate of potassium
and 5 grammes powdered binoxide of manganese, transferring to a retort,
which the mixture should not more than half fill, and heating carefully
over a Bunsen burner. The evolved gas may be collected in a gas-
holder or in an india-rubber bag. The latter is not to be recommended
for use for carbon determinations, as rubber is very liable to give off
hydrocarbons.

44 RE A GENTS.

ALKALIES AND ALKALINE SALTS.

Ammonia. NH4HO.

The solution of ammonia gas (NH3) commonly used is of sp. gr. 0.88,
and contains about 30 to 35 per cent, of ammonia. It should be kept
in glass-stoppered bottles and in a cool place, as the gas passes off very
rapidly even at the ordinary temperature when open to the air. It
should be colorless, leave no residue upon evaporation, be free from
chlorides and sulphates, and give no precipitate with H2S.

Bisulphite of Ammonium. NH4HSO3.

Bisulphite of ammonium is made by passing sulphurous acid gas
into strong ammonia until the solution becomes yellowish in color and
smells strongly of sulphurous acid. By the first method of manufacture
of SO2 given on page 42, a large amount of CO2 is formed at the same
time, which is absorbed by the ammonia. This is gradually displaced
by the SO2, and if the solution is kept cool, white crystals of the
neutral sulphite, (NH4)2SO3H2O, are deposited. These are gradually dis-
solved by the excess of SO2 until the solution becomes quite clear,
assuming a yellowish tint. When copper is used instead of charcoal, no
CO2 is evolved and no carbonate of ammonium is formed. By exposure
to air bisulphite of ammonium is gradually oxidized to sulphate. Old
bisulphite of ammonium always contains a small amount of hyposulphite,
which occasions a precipitate of sulphur when deoxidizing solutions of
ferric salts. It is not now difficult to purchase pure bisulphite of ammo-
nium, but bisulphite of sodium is very apt to contain phosphoric acid.
When made from strong ammonia-water, 18 c.c. of bisulphite will deoxidize
a solution of 10 grammes of iron or steel.

Sulphide of Ammonium. (NH4)2S.

Sulphide of ammonium is made by saturating strong ammonia with
H2S and adding an equal volume of ammonia. The reactions are

NH4HO + H2S = NH4HS + H2O and

NH4HS + NH4HO=-(NH4)2S+H20.
The solution becomes yellow by age or by exposure to the air.

ALKALIES AND ALKALINE SALTS. 45

Chloride of Ammonium. NH4C1.

Chloride of ammonium is a white, crystalline, anhydrous salt, soluble
in about its own weight of water at 100° C., and in 2.7 parts of water
at 1 8° C. It is volatilized when heated without previous fusion. The
salt is usually purified by sublimation. It generally contains a little iron,
but is free from other impurities. To prepare chloride of ammonium for
use in J. Lawrence Smith's method for decomposition of silicates, dis-
solve it in boiling water and evaporate down on a water-bath or air-bath.
When the salt begins to crystallize out, stir vigorously. The crystals
formed will be very small. Drain off the liquid and dry. The salt can
then be readily powdered.

Nitrate of Ammonium. NH4NO3.

Nitrate of ammonium is a white, crystalline salt, soluble in one-half
its weight of water at 1 8° C., and in much less at 100° C. When
dissolved in water it produces great cold. By evaporation it loses
ammonia and becomes acid. When heated it fuses at 108° C., and is
decomposed between 230° C. and 250° C. into water and nitrous oxide,
NH4NO3=2H2O + N2O. It should leave no residue when volatilized.

Fluoride of Ammonium. NH4P1.

Fluoride of ammonium may be made by saturating hydrofluoric acid by
ammonia. The salt crystallizes when left to evaporate over quicklime. It
is slightly deliquescent, and therefore difficult to keep, as the solution
attacks glass.

Acetate of Ammonium. NH4C2H3O2.

Acetate of ammonium is best made by slightly acidulating ammonia
by acetic acid. One volume of strong ammonia-water requires about 2
volumes of acetic acid, 1.04 sp. gr., to neutralize it. It is best to make it
as needed, as it decomposes when kept.

Oxalate of Ammonium. (NH4)2C2O4 + H2O.

Oxalate of ammonium is a white salt, crystallizing in long prisms united
in tufts. It is soluble in 20 parts of water at 18° C.

REAGENTS.

Caustic Soda. NaHO.

Fused sodic hydrate purified by alcohol is sufficiently pure for ordinary
purposes. It forms white opaque masses, having a strong affinity for water.
It dissolves in water with evolution of heat. Pure sodic hydrate is prepared
by allowing metallic sodium to decompose water in a platinum dish. It
must be kept in a silver or platinum bottle, as the solution acts very
rapidly on glass.

Phosphate of Sodium and Ammonium. NaNH4HPO4,4H2O.

Phosphate of sodium and ammonium (microcosmic salt) is a white, crys-
talline salt, soluble in 6 parts of cold and I part of hot water. It should
not be kept in solution for any great length of time, as it attacks glass very
readily. It loses its water of crystallization very easily, and when heated
gives off its ammonia, leaving pure metaphosphate of sodium, which in the
fused condition dissolves metallic oxides in many cases with the production
of characteristic colors, which makes it a valuable reagent for blow-pipe
analysis. It is easily obtained in a state of purity.

Carbonate of Sodium. Na2CO3.

Carbonate of sodium is never quite pure. It always contains small
amounts of silica, alumina, lime, and magnesia, besides sulphuric acid. It
may generally be obtained quite free from phosphoric acid. Every lot
should be carefully examined for all the above impurities, and the amount
per gramme noted, so that the proper subtraction may be made in each
analysis. It is used in solution only for the neutralization of solutions, as
in the determination of manganese by the acetate method, and, as the solu-
tion attacks glass very rapidly, it is best to dissolve the salt only as it is
needed.

Nitrate of Sodium. NaNO3.

Nitrate of sodium is used occasionally instead of nitrate of potassium
in making fusions of ores containing titanic acid. It may be prepared
by acidulating a strong solution of carbonate of sodium with nitric acid,
heating until the water and excess of nitric acid are driven off, and powder-
ing the dry salt.

ALKALINE SALTS. ^

Hyposulphite of Sodium. Thiosulphate of Sodium. Na2S2O3-f SH^O.

Hyposulphite of sodium is very soluble in water, but decomposes
even in tightly-stoppered bottles, sulphate of sodium being formed and
sulphur precipitated. It should, therefore, be dissolved only as used.
The ordinary salt of commerce is sufficiently pure for use.

Acetate of Sodium. NaC2H3O2 -f 3H2O.

Crystallized acetate of sodium dissolves in 3.9 parts of water at 6° C.
It is rarely quite pure, containing, usually, calcium and iron salts, but it
may be used after solution and filtration for partial analyses, as in the
determination of manganese by the acetate method, etc. In complete
analyses it is better to use acetate of ammonium. When the use of
acetate of sodium is unavoidable, it can be made by dissolving C. P. car-
bonate of sodium in acetic acid, boiling off the liberated carbonic acid,
and adding acetic acid to slight acid reaction.

Caustic Potassa. KHO.

Caustic potassa purified by solution in alcohol, filtration, and subse-
quent evaporation to dryness and fusion, is quite pure enough for all the
ordinary purposes of iron analysis. An aqueous solution of 1.27 sp. gr.
is used to absorb carbonic acid in the determination of carbon in iron
and steel, in the determination of carbonic acid in ores, etc. 300 grammes
of fused KHO dissolved in I litre of water will give a solution of about
this strength.

Nitrite of Potassium. KNO2.

Nitrite of potassium is used to separate nickel and cobalt. It is very
difficult to buy the pure salt, but it is easily made as follows : Heat I
part of nitrate of potassium in an iron dish until it is just fused, then add,
with constant stirring, 2 parts of metallic lead. Raise the heat slightly
to complete the oxidation of the lead, and allow the mass to cool. Treat
the mass with water, filter from the oxide of lead, pass CO2 through the
solution to precipitate the greater part of the dissolved lead, and filter. To
the filtrate add a little sulphide of ammonium to precipitate the last traces

48 REAGENTS.

of lead, filter, evaporate to dryness, and fuse in a platinum dish to decom-
pose any hyposulphite that may have been formed, and preserve the
fused salt for use. Nitrite of potassium is deliquescent.

Nitrate of Potassium. KNO3.

Nitrate of potassium is a white, crystalline salt, anhydrous, and soluble
in 7^ parts of water at o° C, and in 0.4 part of water at 1 00° C. It
melts below a red heat to a colorless liquid, and at a red heat gives off
oxygen gas more or less contaminated by nitrogen, being converted into
nitrite and oxide of potassium. The salt may be purchased in a sufficient
state of purity for all purposes of iron analysis, but, as it may contain
small amounts of sulphuric acid, the amount should always be determined
and the proper allowance made when it is to be used for the estimation
of sulphur in ores.

Sulphide of Potassium. K2S.

Sulphide of potassium is made by passing H2S into a solution of
caustic potassa and filtering from any precipitated alumina or sulphide
of iron. It is used instead of the corresponding ammonia-salt when the
solution contains copper, as sulphide of copper is slightly soluble in
sulphide of ammonium.

Bichromate of Potassium.
Bichromate of potassium is an orange-colored, anhydrous, crystalline
salt, soluble in 20 parts of water at o° C., and in I part of water at
1 00° C. It melts below a red heat to a transparent red liquid, crum-
bling to powder upon cooling. Heated with strong H2SO4 it gives off
about one-sixth its weight of oxygen gas, the reaction being K2Cr2O7 -f-
4H2SO4=Cr2K2(SO4)4-f4H2O + 3O. It is readily obtained in a state of
purity, but should always be fused to destroy any organic matter before
being used to determine carbon in iron or in ores.

Chlorate of Potassium. KC1O3.

Chlorate of potassium is a white, crystalline, anhydrous salt. It is
soluble in about 30 parts of water at o° C., and in about 2 parts at 100° C.

POTASSIUM SALTS. ^

It is readily decomposed by heat, first into a mixture of chloride and per-
chlorate of potassium, a portion of the oxygen being set free, and at a
higher temperature the perchlorate is decomposed, the remaining oxygen
is given off and chloride of potassium alone remains. It is easily obtained
in a sufficient state of purity for use in iron analysis. Heated with nitric
acid it yields nitrate and perchlorate of potassium, water, chlorine, and
oxygen, thus :

Heated with hydrochloric acid it gives chloride of potassium, water, and
a mixture of peroxide of chlorine and chlorine, called euchlorine, thus :

4KC103 + 1 2HC1 =4KC1 + 6H20 + 3C1O2 + 9C1.

Bisulphate of Potassium. KHSO4.

Bisulphate of potassium is a white, crystalline salt, soluble in about one-
half its weight of boiling water. A large amount of water decomposes it
into sulphate of potassium and free sulphuric acid ; even in the presence of
a large excess of sulphuric acid the neutral salt crystallizes out, leaving free
sulphuric acid in the solution. Bisulphate of potassium melts at 197° C. ;
at higher temperatures it gives off water, leaving the anhydrous salt, and at
a red heat it gives -off sulphuric acid, leaving the neutral sulphate. It is
difficult to obtain it very pure, but it may be made as follows : Dissolve
bicarbonate of potassium in water, filter, and from a graduated vessel add
H2SO4 until, after boiling ofT the liberated CO2, the solution is neutral, or
but very faintly alkaline to test-paper. Filter, if necessary, and to the fil-
trate add as much H2SO4 as was added in the first place to neutralize the
bicarbonate. Boil the solution down, and finally fuse the mass in a platinum
dish. Cool it, and when it is almost ready to solidify pour it into another
dish. Break it up, and preserve it in glass-stoppered bottles.

Iodide of Potassium. KI.

Iodide of potassium is a white, crystalline, anhydrous salt, very soluble
in water, and in dissolving it causes a fall of temperature in the solution.
It is soluble in about 0.8 part of water at o° C., and in 0.5 part of

£0 REAGENTS.

water at 100° C. It is soluble in 6 parts of alcohol at the ordinary
temperature, and, when dissolved, the addition of HC1 does not turn it
brown if it is free from iodate. A solution of I part of iodide of
potassium in 2 parts of water will dissolve 2 parts of iodine, but upon
dilution some of the iodine is precipitated.

Permanganate of Potassium. KMnO4,

Permanganate of potassium is a dark purple-red, anhydrous salt,
crystallizing in long needles. It is soluble in 16 parts of water at 15° C.
It is easily obtained very pure, but the solution should always be filtered
through ignited asbestos, as paper has a strong reducing action on it.

Perrocyanide of Potassium. K4Pe2Cy6 -f 3H2O.

1 Ferrocyanide of potassium is a yellow, crystalline salt, soluble in 4
parts of water at o° C., and in 2 parts of water at 100° C. It is used
as a reagent to show the presence of ferric salts, which produce a blue
coloration, caused by the formation of ferrocyanide of iron (Prussian blue).

Ferricyanide of Potassium. K3Fe2Cy6.

Ferricyanide of potassium is a blood-red, anhydrous, crystalline salt,
soluble in about 3.1 parts of water at o° C., and in 1.3 parts of water at
100° C. The dilute solution, like that of the ferrocyanide, is yellow in
color. Ferrous salts added to the solution give a blue coloration, due
to the formation of ferrous ferricyanide, while ferric salts produce no
change of color. The ferricyanide should never be kept in solution.

SALTS OF THE ALKALINE EARTHS.

Carbonate of Barium. BaCO3.

Carbonate of barium prepared by precipitation is a soft white powder.
It is difficult to obtain it in a state of purity, but it is easily prepared
by adding a solution of carbonate of ammonium to a clear boiling solu-
tion of chloride of barium, washing the precipitated carbonate of barium
with hot water, first by decantation and afterwards on a filter. The car-

ALKALIES AND ALKALINE SALTS. ^

bonate of ammonium should, of course, be free from sulphate. The
thoroughly washed carbonate of barium should be transferred to a bottle
and shaken up with water, in which condition it is ready for use. Car-
bonate of barium is very slightly soluble in water, requiring, according to
the different authorities, from 4,000 to 25,000 parts of water to dissolve
it. It is poisonous.

Acetate of Barium. Ba,(C,£lBO2)2.

Acetate of barium may be prepared by dissolving pure carbonate of
barium in acetic acid. It crystallizes with I or 3 molecules of water, but
dried at o° C., or exposed to the air, it effloresces and yields the anhy-
drous salt as a white powder. It is very soluble in water, dissolving in
about 2 parts of water at o° C., and in about I part at 100° C. When
heated it decomposes into acetone and carbonate of barium, thus :
Ba(C2H302)2= C3H60 + BaCO3.

Chloride of Barium. BaCl2,2H2O.

Chloride of barium is a white, crystalline salt, soluble in about 3
parts of water at 15° C., and in about i}4 parts at 100° C. Heated to
100° C. it loses its water of crystallization, yielding the anhydride as a
white mass, which melts at a full red heat. Chloride of barium is almost
insoluble in strong HC1. It is used almost exclusively for the determina-
tion of sulphuric acid, and may be kept in solution for this purpose.
100 grammes of the crystallized salt dissolved in I litre of water is a
good proportion to use. Of this solution 10 c.c. will precipitate 1.16
grammes of BaSO4, equal to 0.4 gramme SO3 or 0.16 gramme S.

Caustic Baryta. Hydrate of Barium. BaH2O2,8H2O.
Hydrate of barium is a white, crystalline salt, soluble in 20 parts of
water at 15° C., and in 3 parts of water at 100° C. The anhydride
may be prepared by heating nitrate of barium to redness in a platinum
crucible, raising the heat gradually at first to avoid loss from frothing.
It attacks platinum, however, at a high temperature. The solution has
a strong affinity for carbonic acid, absorbing it readily from the air, the

ij 2 REAGENTS.

carbonate of barium so formed causing a scum on the surface of the
solution. The solution attacks glass very strongly.

Chloride of Calcium. CaCl2.

Crystallized chloride of calcium loses all its water of crystallization
at 200° C, yielding the white porous anhydrous chloride, which is very
deliquescent. The anhydrous salt fuses at a low red heat, but is partly
changed to oxide. For this reason the fused salt should never be used
for drying CO2 in the determination of this gas, as some of it is taken
up by the oxide of calcium. A solution of chloride of calcium con-
taining 59 parts of the anhydrous salt to 100 parts of water boils at
115° C., a saturated solution at 179.5° C.

Carbonate of Calcium. CaCO3.

Pure carbonate of calcium, for use in Prof. J. Lawrence Smith's
method for the determination of alkalies in silicates, is prepared as
follows: Dissolve marble or calcite, free from magnesia, in dilute HC1,
add an excess of powdered marble, heat the solution, and add some
milk of lime to precipitate magnesia, phosphate of calcium, etc. Filter,
heat the solution almost to boiling, and precipitate by carbonate of
ammonium. The carbonate of calcium formed will be a very dense
powder, which will settle readily and be easily washed. Wash thor-
oughly, dry, and preserve for use.

METALS AND METALLIC SALTS.

Metallic Copper.

Metallic copper absorbs chlorine gas at ordinary temperatures, and is
used in iron analysis to absorb any chlorine that may be given off during
the combustion of the carbonaceous matter liberated by the action of sol-
vents on iron and steel. It is used in the form of drillings, which should
be taken with a perfectly dry drill, and which should be free from oil
and grease. The drillings should be kept in a stoppered bottle, and may
be used as long as they are perfectly bright and clean.

COPPER SALTS. 53

Sulphate of Copper. CuSO4,5H2O.

Sulphate of copper is a blue, crystalline salt, soluble in 2.7 parts of
water at 18° C., and in 0.55 part of water at 100° C. The aqueous
solution of the neutral salt is strongly acid to litmus-paper. The crystals
of sulphate of copper effloresce on the surface when exposed to the air;
heated to 1 00° C. they lose 4 molecules of water, and when heated to
200° C. they lose the remaining molecule. The anhydrous salt is a white
saline mass, which is decomposed at a bright-red heat, giving off sul-
phurous acid and oxygen and leaving cupric oxide. The anhydrous salt
has a strong affinity for water, and also for hydrochloric acid gas. A
solution of sulphate of copper dissolves metallic iron, the copper being
precipitated from the solution at the same time in a spongy mass.

Anhydrous Sulphate of Copper.

The property anhydrous sulphate of copper possesses of absorbing
hydrochloric acid gas makes it useful in the determination of carbon by
combustion, and it is best prepared for this purpose as follows : Heat
crystals of sulphate of copper, about the size of a coffee bean, in a
porcelain dish until the blue color of the crystals disappears and they
become white. Transfer while still hot to a dry, glass-stoppered bottle.

Anhydrous Cuprous Chloride. CuCl.

To prepare the granulated salt for use as an absorbent of hydrochloric
acid and chlorine in carbon determinations, moisten the ordinary powdered
salt of commerce in a porcelain dish and rub it up with a glass rod into
little lumps about the size of a coffee bean. Heat it gradually until the
water is expelled and the lumps, which will be dark brown in color, harden.
Transfer to a glass-stoppered bottle.

Cupric Chloride. CuCl2-J-Aq.

To prepare cupric chloride for use in dissolving "iron or steel for the
determination of carbon, grind up equal weights of sulphate of copper and
common salt in a porcelain mortar, and pour over the mixture a small
amount of water heated to 5O°-6o° C. The liquid becomes emerald-green

54 REAGENTS.

in color, and deposits upon evaporation sulphate of sodium. Decant from
the deposited salt and evaporate again until the solution is reduced to a
very small bulk. Cool, and decant from the remainder of the sulphate of
sodium and the excess of chloride of sodium. By further evaporation and
cooling the cupric chloride may be obtained in the form of green crystals.
These crystals are deliquescent. The solution should be diluted and filtered
through asbestos.

Double Chloride of Copper and Ammonium. 2(NH4Cl),CuCl2,2H2O.
Double Chloride of Copper and Potassium. 2(KCl),CuCl2,2H2O.

The double chloride of copper and ammonium is a bluish-green crystal-
line salt, quite soluble in water.

The double chloride of copper and potassium is bluish-green likewise
and more soluble than the ammonium salt. The recent experiments of the
American members of the International Steel Standards Committee have
shown that the double chloride of copper and ammonium is nearly always
impure, from the presence of hydrocarbons in the chloride of ammonium,
derived probably from the gas liquor from which ammonia salts are dis-
tilled. These hydrocarbons unite with the carbonaceous residue liberated
from steel and iron in the process of determining carbon, and of course
vitiate the results. Several recrystallizations free the salt to a certain
extent from this impurity. The use of the potassium salt is not open to
this objection.

To prepare these salts proceed as follows: Dissolve 107 parts of
chloride of ammonium or 149.1 parts of chloride of potassium and 170.3
parts of crystallized cupric chloride (CuCl2,2H2O) in water and crystallize
out the double salt. Dissolve about 300 grammes of the double salt in
i litre of water, filter through ignited asbestos, and preserve for use in
glass-stoppered bottles.

Oxide of Copper. CuO.

Oxide of copper, both fine and coarse, for combustions is easily obtained.
It may be prepared as follows : Dissolve metallic copper in nitric acid, evap-
orate to dryness in a porcelain dish, transfer it to a Hessian crucible, and

COPPER AND IRON SALTS. ^

heat it in a furnace until no more nitrous fumes are given off. Keep the
crucible well covered to prevent any coal getting into it, and avoid raising
the heat too high, or the mass will fuse. Stir it from time to time, and
when finished the oxide on top will be in a fine powder, while that in the
bottom of the crucible will have sintered. Rub it up in a mortar and
pass through a fine metal sieve. Keep the two kinds, fine and coarse,
separate in glass-stoppered bottles, carefully covered to preserve them

from dust.

Iron Wire.

Very fine soft piano-forte wire is the best form of iron to use when
standardizing solutions of permanganate or bichromate of potassium by
metallic iron. Wrap one end of a piece of wire, about 2 feet (610 mm.)
long, around a lead-pencil, and, using this as a handle, draw the wire
several times through a piece of fine emery-cloth, then through a fold
of dry filter-paper, then, holding the wire with the paper, wrap it around
the pencil. Cut -off the end that has not been cleaned, and the little
spiral of wire will be in a convenient form for weighing.

Ferrous Sulphate.

Ferrous sulphate (green vitriol, or copperas) is a bluish-green crystal-
line salt, soluble iru 1.64 parts of water at 10° C, and in 0.3 part at 100° C.
It is insoluble in alcohol. The crystals lose 6 molecules of water when
heated to 114° C., but retain the last molecule even at 280° C. Heated to
a red heat the anhydrous sulphate is decomposed, giving off sulphurous
acid and leaving a basic ferric sulphate, which at a higher temperature is
entirely decomposed, leaving only ferric oxide. To prepare the crystals
for use in volumetric analysis, add alcohol to the aqueous solution of the
ferrous sulphate, when the salt is precipitated as a bluish-white powder.
Filter, wash with alcohol, dry thoroughly, and preserve in glass-stoppered
bottles. The salt prepared in this way remains unaltered for a long time.

Double Sulphate of Iron and Ammonium. FeSO4(NH4)2SO4,6H2O.

The double sulphate of iron and ammonium is a light green crystalline
salt, soluble in 2.8 parts of water at 16.5° C. It may be prepared as

56 REAGENTS.

follows : Dissolve 276 grammes of crystallized ferrous sulphate in water,
filter, and add to the filtrate a clear solution of sulphate of ammonium
( (NH4)2SO4, Glauber's Sal Secretum), evaporate down, and allow the
double salt to crystallize out. Drain the crystals, wash slightly with cold
water, and dry on blotting-paper. When perfectly dry, preserve in a
glass-stoppered bottle. The crystals remain unaltered for a long time
even in moist air. They contain exactly \ their weight of metallic iron.

Mercurous Nitrate. Hg>NO3,H2O.

To prepare this salt, pour cold, moderately strong HNO3 on an excess
of metallic mercury, and when the violent action has subsided, pour off
the acid and allow the salt to crystallize out by the cooling of the acid.
The salt is soluble in a small amount of water, but a large amount de-
composes it into a basic salt and free acid.

Mercuric Oxide. HgO.

Mercuric oxide is a light orange-yellow substance when prepared by
precipitation from a mercuric salt. To a dilute solution of mercuric
chloride add a slight excess of caustic potassa, allow the precipitate to
settle, wash it thoroughly by decantation with hot water, and finally wash
it into a glass-stoppered bottle. It is used shaken up with water.

Chromate of Lead. PbCrO4.

Fused chromate of lead is a dark brown mass showing a radiated
structure, and when powdered it is dark yellow in color, very heavy,
and slightly hygroscopic. It is easily obtained very pure, but may be
made as follows : Dissolve acetate of lead in water, add a little acetic
acid, filter, and precipitate by a solution of bichromate of potassium.
Wash by decantation, and finally on linen, dry, and heat in a Hessian
crucible until the mass is just fused. Pour on a polished iron slab, grind
in a clean mortar, and preserve the powder in glass-stoppered bottles,
covered to exclude dust. Chromate of lead heated to a full red heat
gives off oxygen and is reduced to a mixture of basic chromate of lead
and oxide of chromium.

LEAD SALTS. H?

•>'

Peroxide of Lead. PbO2.

Peroxide of lead is rather difficult to obtain in a state of purity; it
is liable to contain nitrate of lead and oxide of manganese. The latter
element interferes materially with its use as a reagent in the determina-
tion of manganese by the color test. It should always be carefully ex-
amined by boiling with dilute nitric acid, and, if it imparts any color to
the solution, must be promptly rejected. It may be readily prepared by
digesting red oxide of lead in dilute nitric acid, decanting off the nitrate
of lead, and washing the residue thoroughly with hot water. Red oxide
of lead by this treatment is decomposed into protoxide of lead, which
dissolves in the nitric acid, and peroxide, which remains insoluble. Per-
oxide of lead is a heavy brown powder, which, when heated, gives off
oxygen and is converted into red lead or protoxide of lead.

Oxide of Lead dissolved in Caustic Potassa.

Pour a cold solution of nitrate of lead into caustic potassa, 1.27 sp.gr.,
stirring constantly to dissolve the oxide of lead, which precipitates. Add
the nitrate of lead until a permanent precipitate is produced. Allow this
to settle, and siphon the clear liquid into a glass-stoppered bottle. It is
well to coat the stopper with a little paraffine, to prevent its sticking.

Platinic Chloride Solution.

Dissolve platinum-foil in HC1, adding HNO3 from time to time,
evaporate to dry ness on the water-bath, redissolve in HC1, and evaporate
again to drive off the HNO3. Redissolve in water with the addition of
a few drops of HC1, filter, and preserve in a bottle the stopper and neck
of which are protected by a ground-glass cap to prevent any access of
ammonia to the solution.

Metallic Zinc.

Melt zinc, which should be as free as possible from lead and iron,
in a Hessian crucible, and pour it in a thin stream from a height of
four or five feet into a bucket of cold water, giving the crucible a cir-

5 8 REAGENTS.

cular motion to prevent the zinc from falling in exactly the same place
all the time. Pour off the water, dry the granulated zinc, and preserve
it in bottles for use.

Oxide of Zinc in Water.

Emmerton* suggests the following method of preparing this reagent:
Dissolve ordinary zinc white in HC1, add the zinc white until there is
an excess which will not dissolve, then add a little bromine-water, heat
the solution, filter, and precipitate the oxide of zinc by ammonia, being
careful to avoid an excess. Wash thoroughly by decantation, and then
wash into a bottle. Shake the bottle well, to diffuse the oxide through
the water, before using.

REAGENTS FOR DETERMINING PHOSPHORUS.

Magnesia Mixture.

Dissolve 1 10 grammes of crystallized chloride of magnesium (MgCl2
-f-6H2O) or 50 grammes of the anhydrous salt in water, and filter. Dis-
solve 28 grammes of chloride of ammonium in water, add a little bro-
mine-water and a slight excess of ammonia, and filter. Add this solution
to the solution of chloride of magnesium, add enough ammonia to make
the solution smell decidedly of ammonia, dilute to about 2 litres, transfer
to a bottle, shake vigorously from time to time, allow to stand for
several days, and filter into a small bottle as required for use. 10 c.c.
of this solution will precipitate about 0.15 gramme P2O5.

Molybdate Solution.

Weigh into a beaker 100 grammes of pure molybdic anhydride, mix it
thoroughly with 400 c.c. of cold distilled water and add 80 c.c. of strong
ammonia (0.90 sp. gr.). When solution is complete, filter and pour the
filtered solution slowly with constant stirring into a mixture of 400 c.c. of
strong nitric acid (1.42 sp. gr.) and 600 c.c. of distilled water. Allow to settle
for 24 hours and filter. A solution prepared in this way will keep for sev-
eral months even in hot weather without any deposition of molybdic acid.

* Trans. Am. Inst. Min. Engineers, vol. x. p. 201.

METHODS FOR THE ANALYSIS

PIG-IRON, BAR-IRON, AND STEEL.

DETERMINATION OF SULPHUR.

By Evolution as H2S.

KARSTEN was the first to suggest dissolving iron or steel in
HC1, or dilute H2SO4, and collecting the evolved H2S by ab-
sorbing it in a solution of a metallic salt. He recommended
CuCl2.

Absorption by Alkaline Solution of Nitrate of Lead.

The apparatus, Fig. 47, shows the usual arrangement for
carrying out the process, with the addition of the generating-
bottles for supplying hydrogen gas. This is the apparatus
described under the head of " Apparatus for Generating CO2,"
page 42. The wash-bottle A contains an alkaline solution of Description

of the ap-

nitrate of lead, and is connected with the funnel-tube by the
rubber tube B, and a small piece of glass tubing, C, turned at
a right angle with one end drawn down and covered with a
short piece of rubber tubing. This fits in the neck of the bulb
of the funnel-tube and makes a tight joint. The analytical
process is conducted as follows :

Weigh 10 grammes * of borings or drillings, free from lumps,

* A 5-factor weight (6.878 grammes) is a better amount to take, as, when the
weight of BaSO4 found is multiplied by two, each milligramme is one-thousandth of
a per cent, of sulphur.

ANAL YSIS OF IRON AND STEEL.

FIG. 47.

DETERMINATION OF SULPHUR. 6j

into the previously dried flask D, and close it with the rubber Description

of the

stopper fitted with a funnel-tube and a delivery-tube. The outlet- process,
tube from the flask D connects with the tube Ft reaching almost
to the bottom of the Erlenmeyer flask H. In each of the flasks
H are poured about 20 or 30 c.c. of potassium hydrate solu-
tion of nitrate of lead* and enough water to fill them two-
thirds full. Connect the apparatus, and run a slow stream of ,

I estmg the

hydrogen through until all the air is expelled, then close the ^p^atus.
glass stopcock of the funnel-tube, and shut off the supply of
hydrogen by closing the small glass stopcock K. If the con-
nections are all tight, the liquid will not recede in the tube F.
When this is assured, disconnect the tube C, and fill the bulb
— which should be of about 100 c.c. capacity — with a mixture
of 50 c.c. of strong HC1 and 50 c.c. of water. Replace the tube Ct
turn on the hydrogen, and open the stopcock of the funnel-tube,
so as to allow the acid to flow into the flask D. When the acid
has all run into the flask, regulate the flow of the hydrogen so
that the gas shall pass through the solutions in the flasks H, H1
as rapidly as possible, and heat the flask D. When the solu-
tion in the flask D has boiled for fifteen minutes, and all the
metal has dissolved, remove the source of heat and continue
the current of hydrogen for about ten minutes, regulating its
flow by means of the stopcock K, to prevent any reflux of the
liquid in H, which might be caused by the cooling of the flask
D. Shut off the hydrogen, disconnect the apparatus, and wash
the contents of the flask H into a No. 2 Griffin's beaker. Un-
less a precipitate of sulphide of lead appears in the second flask Treatment
Hr, it need not be emptied, but the same solution can be used precipitate.
over again for the next analysis. Collect the precipitate in a
small filter, wash it once or twice with hot water, and, while
still moist, throw the filter and precipitate back into the beaker,
in which have been placed just the instant before some powdered

See page 57.

ANAL YSIS OF IRON AND STEEL.

KC1O3 and from 5 to 20 c.c. of strong HC1, according to the
amount of the precipitate of lead sulphide. Allow it to stand
in a warm place until the fumes shall have partly passed off,
then add about twice its volume of hot water, and filter into a
No. I beaker. Wash with hot water, heat the filtrate to boiling,
and add NH4HO until the solution is slightly alkaline to litmus-
paper. Acidulate with a few drops of HC1, add 5 to 10 c.c. of
BaCl2 solution,* boil 15 or 20 minutes, and stand aside for half
an hour. Filter the precipitate of BaSO4, preferably on a Gooch
Baso4. perforated crucible, wash with hot water, ignite, and weigh as
BaSO4, which contains 13.75 Per cent. S. It is -always well to
test the alkaline filtrate from the lead sulphide with a few drops
of the lead solution, for it might happen that all the lead would
be precipitated from the solution as sulphide, and an excess of
H2S remain in the solution as sulphide of potassium.

The entire operation described above can be performed in
about two and a half hours, and is, in my opinion, the most ac-
curate method known for the determination of sulphur in steel.

Absorption by Ammoniacal Solution of Sulphate of Cadmium.

f. f. Morrell f passes the evolved gas into an ammoniacal
solution of sulphate of cadmium. Prepare a solution of sulphate
of cadmium of convenient strength, and add enough ammonia to
redissolve the precipitate and give a clear solution. Place this
solution in the bottles H, H, and proceed as usual. Filter the
precipitate of sulphide of cadmium in a counterpoised filter, wash
with water containing a little ammonia, dry at 100° C., and
weigh as CdS, which contains 22.25 Per cent- °f S.

Absorption by Ammoniacal Solution of Nitrate of Silver.
Berzelius proposed the use of a dilute solution of nitrate of
silver made alkaline by ammonia. The method of procedure is

* See page 51. f Chem. News, xxviii. 229.

DETERMINATION OF SULPHUR. 63

as follows : Dissolve I gramme of AgNO3 in a small quantity of Preparation
water, and make it strongly alkaline with NH4HO ; pour about

two-thirds of the solution into the first of the bottles H, and
the remainder into the second, and fill up to the proper level silver-
with water. Proceed exactly as described above until the sul-
phide of silver has been filtered off and washed. Dry this pre-
cipitate carefully at a low temperature, say 100° C, and brush
it carefully into a small, dry beaker, returning the filter to the
funnel. Pour into the bottles H, should any of the sulphide
remain adhering to the sides, 20 or 30 c.c. strong HNO3, and
when it is all dissolved, pour the acid in the filter, allowing it
to run into the beaker containing the sulphide of silver, and Details of
wash out the bottles with a little HNO3, allowing this to run
over the filter also. Digest the sulphide of silver until it is all
dissolved, then dilute with hot water, add an excess of HC1,
and filter off the chloride of silver. Add a small amount of
carbonate of sodium, and evaporate nearly dry, dilute, add a
few drops of HC1, filter if necessary, and precipitate as before
by chloride of barium. Even when the sample contains no
sulphur a slight precipitate of carbide of silver may be thrown
down by the carburetted hydrogen evolved from the iron or
steel by the action of the acid.

Absorption and Oxidation by Bromine and HCl.

Fresenius * suggested passing the evolved gases through a Advantage
solution of bromine in HCl, which has the advantage of oxidiz- method.

ing the sulphuretted hydrogen at once, but the disadvantage of
filling the room with bromine-fumes unless the apparatus is placed
under a hood with a good draft. It is necessary when using this
method to avoid bringing the bromine-fumes in contact with
rubber stoppers. Instead of the bottles H, attach to the exit-tube Description
a bulb-tube of the shape shown in Fig. 48, containing 3 to 5 °atus.Pa

* Fresenius, Zeitschrift, xiii. 37.

ANAL YSIS OF IRON AND STEEL.

Details of
the
method.

FIG. 48.

c.c. of bromine and enough HC1 to fill the bulb-tube to the
marks shown in the cut. When the operation is finished, wash

the contents of the bulb-tube out into
a beaker, heat until the bromine is all
driven off, neutralize by NH4HO, and
precipitate the sulphuric acid exactly as
described on page 62. Instead of neu-
tralizing by NH4HO, the HC1 solution
may be evaporated down nearly to dry-
ness after adding a little carbonate of
sodium or the solution of chloride of
barium; but repeated experiments have
shown that sulphate of barium is prac-
tically insoluble in chloride of ammonium, so that the plan of

of BaSO4

in NH4ci. neutralizing by NH4HO, being the shorter and less troublesome,
is to be preferred.

Absorption and Oxidation by Permanganate of Potassium.

Drown * suggested the use of permanganate of potassium solu-
tion as an absorbent and oxidizer ; the process being carried out
as follows : Make a solution of permanganate of potassium, 5
grammes to the litre of water, and fill the bottles H to their
proper height with this liquid, using three bottles, however, instead
of two, and proceed with the operation as before described, being
Avoid rapid careful to avoid a rapid evolution of the gas. Wash the con-

evolution

of gas. tents of the bottles H into a clean beaker, dissolve any oxide
of manganese that may adhere to the sides of the bottles in HC1,
add this to the solution in the beaker, and then add enough HC1
to decompose the permanganate entirely. Boil until the solu-
tion is colorless, filter if necessary, and precipitate by chloride
of barium. Allow it to stand overnight, filter, wash, ignite, and
weigh the BaSO4.

Details of
the pro-
cess.

Journal Inst. Min. Engineers, ii. 224.

DETERMINATION OF SULPHUR. &

Absorption and Oxidation by Peroxide of Hydrogen.

Craig * suggested the use of ammoniacal solution of peroxide
of hydrogen in the absorbing-bottles. Attach to the exit-tube
of the flask D (Fig. 47) a nitrogen-bulb of the usual form (Fig.
48), in which have been placed 4 c.c. of peroxide of hydrogen
and 1 6 c.c. of ammonia, and proceed as before directed. When
the operation is finished, wash the contents of the nitrogen-bulb Necessity
into a small beaker, acidulate slightly with HC1, boil, add chlo- deter-
ride of barium, and determine the amount of BaSO4 as usual.
As peroxide of hydrogen always contains sulphuric acid, the
amount must be carefully determined in each fresh lot of the peroxide

of hydro-

H2O2, and the proper correction made for the volume used. gen.

By Oxidation and Solution.

Many chemists still prefer the old method of oxidizing and This method
dissolving the metal and precipitating the sulphuric acid in the by many
solution by chloride of barium. The details are as follows :
Treat 5 grammes of drillings in a No. 4 Griffin's beaker, covered
by a watch-glass with 40 c.c. of strong HNO3. This requires
care, for drillings of bar-iron and low steel are often acted on so
violently, even by strong HNO3, as to cause the solution to boil
over. In this case it is best to place the beaker in a dish con-
taining a little cold water and to add the acid gradually. When
all the acid has been added and the action has ceased, some
small particles generally remain undissolved, and their solution
is effected by heating the beaker on the sand-bath and finally
by adding a few drops of HC1. With pig-iron and steel there Precautions
is usually no action in the cold, and in this case heat the beaker
carefully until the action begins, then stand the beaker in a
cooler place, and if the action becomes very violent, stand the HN°8
beaker in cold water until it moderates. Very high carbon steels

* Chem. News, xlvi. 199.
5

66 ANALYSIS OF IRON AND STEEL.

dissolve with great difficulty even in boiling acid ; but the solu-
tion may be hastened by adding a few drops of HC1 from time
to time. When solution is complete and only particles of
graphite and silica remain undissolved, which is shown by the
residue being entirely flotant, remove the cover, add a little
carbonate of sodium, and evaporate the solution to dryness in
the air-bath. The addition of the carbonate of sodium is to
prevent any possible loss of sulphuric acid, which might other-
wise occur by the decomposition of the sulphate of iron at a

Further de- high temperature. Remove the beaker from the air-bath, and
when cold add 30 c.c. HC1, and heat until the oxide of iron is
dissolved, evaporate again to dryness to render the silica insol-
uble, redissolve in HC1, evaporate until the ferric chloride begins
to separate out, add 2 c.c. HC1 and a little water. Filter and
wash, being careful that the total filtrate and washings shall not
excede 100 c.c. in volume. Heat the filtrate to boiling, add
10 c.c. saturated solution of chloride of barium, and allow it to

whenig- stand in the cold over night. Filter, wash with a little very
dpitate dilute HC1, and finally with cold water; dry, ignite, and weigh

as BaSO4. If this ignited precipitate is reddish in color, it shows
that Fe2Q3 has been precipitated with the BaSO4. In this case
fuse wjth Na2CO3, dissolve in water, filter, acidulate the filtrate,
and precipitate as before. Or, filter the aqueous solution of the
fusion, dissolve in HC1, precipitate by ammonia, weigh the Fe2O^
and subtract from the weight of BaSO4.

Notes and Precautions.

The investigations of Phillips* and Matthewmanf have shown
conclusively that in many pig-irons, the evolution method fails to
give the full sulphur contents. This seems to be due to the
formation of organic sulphides, probably of the mercaptan series,
and not to the presence of copper or arsenic, as has been sup-

* Journal American Chem. Society, vol. xvii. p. 891.

f Journal West of Scotland Iron and Steel Institute, vol. iii. p. 27.

DETERMINATION OF SULPHUR.

posed. As those compounds are quite volatile and very difficult
to oxidize, some portions seem to pass through the absorbing
solutions, while under certain circumstances other portions
remain in the evolution flask with great persistency and are
expelled only after long boiling.

The only practicable method for pig-irons of this character,
therefore, is the oxidation method.

There are three precautions to be observed in using this
method. I. The sample should be dissolved in strong nitric
acid, as, when dilute nitric acid, or even aqua regia, is used,
some sulphur seems to escape oxidation.

2. The amount of acid in the solution from which the
barium sulphate is precipitated must be most carefully regulated,
as well as the absolute volume of the solution.

3. The reagents used must be examined for sulphuric acid.
This is best done as follows : Measure into a beaker the total
amount of acid, both nitric and hydrochloric, used in the
determination, add a little sodium carbonate and evaporate to
dryness. Redissolve in 15 c.c. of water and 5 or 10 drops of
hydrochloric acid, filter, heat to boiling, add 10 c.c. of barium
chloride, boil 10 or 15 minutes, allow to settle, filter, wash,
ignite, and weigh as BaSO4. The amount found is to be ab-
stracted from the total weight of BaSO4 found in the sample.

In the use of the evolution method for steels, the results
obtained vary somewhat with the solution used for absorbing
the hydrogen sulphide, and I am satisfied that the best absorbent
is the alkaline solution of lead nitrate. I have never failed, so
far as I know, in getting correct results with this absorbent in
any steel. The evolution of the gas should be as rapid as pos-
sible, as there seems to be no danger of any hydrogen sulphide
passing the liquid in the first flask, and the operation is naturally
shortened. If the solution containing the precipitated barium
sulphate is boiled vigorously for 15 or 20 minutes, it is not
necessary to allow it to stand more than half an hour, so that a

68 ANALYSIS OF IRON AND STEEL.

determination can be made in two hours, or two hours and a
half, without any trouble.

RAPID METHOD.
Volumetric Determination by Iodine.

This method, suggested by Elliott,* involves the evolution of
the sulphur as H2S, its absorption in a solution of sodium hy-
drate, and titration by iodine in iodide of potassium. It requires
a standard solution of iodine, a standard solution of hyposul-
phite of sodium, a starch solution, and a standard solution of
bichromate of potassium.

Iodine Solution.

Dissolve 6.5 grammes pure iodine in water with 9 grammes
iodide of potassium, and dilute to I litre.

Hyposulphite of Sodium Solution.

Dissolve 25 grammes hyposulphite of sodium in water, add
2 grammes carbonate of ammonium, and dilute to i litre. The
carbonate of ammonium retards the decomposition of the hypo-
sulphite of sodium.

Starch Solution.

Weigh into a porcelain or Wedgwood mortar i gramme of
pure wheat starch, and rub it to a thin cream with water.
Pour it into 150 c.c. boiling water, allow it to stand until cold,
and decant the clear solution. The addition of 10 or 15 c.c.
glycerine makes the solution keep better. It is better, how-
ever, to make a fresh starch solution every few days.

Dr. Waller recommends Miiller's suggestion of grinding the
starch with a strong solution of potassium or sodium hydrate
and dissolving in hot water for use. It keeps indefinitely.

Bichromate of Potassium Solution.

Dissolve 5 grammes pure bichromate of potassium in water,
and dilute to i litre.

* Chem. News, xxiii. 61.

RAPID METHODS FOR SULPHUR. £g

All these solutions should be placed in glass-stoppered bottles
and kept in a dark place.

Standardizing- the Solutions.

Standardize the bichromate solution as directed in the "Anal-
ysis of Iron Ores." When bichromate of potassium is added Reaction
to iodide of potassium in presence of free HC1, iodine is liber- K2cr2o7is
ated, in accordance with the formula K2Cr2O7 + 6KI+ I4HC1 Kiwith°
= 8KCl+CraCl6+7HaO + 6I, or i equivalent of K2Cr2O7 = eHx^sof
294.5 liberates 6 equivalents of iodine =761. 1. Therefore, by
adding to a solution of iodide of potassium in the presence of
HC1 a known amount of bichromate, we can calculate the ab-
solute amount of iodine liberated, and by titrating this solution
by the hyposulphite solution we can accurately standardize the
latter. The reaction which takes place when a solution of Reaction of
hyposulphite (thiosulphate) of sodium is acted on by iodine is Phite of
2NaHS2O3 + 2! = 2HI + Na2S4O6> or 2 equivalents of thiosul- ^3™.
phate unite with 2 equivalents of iodine to form hydriodic acid
and tetrathionate of sodium. By adding a few drops of starch
solution to a solution containing iodine, blue iodide of starch is
formed, and colors the solution as long as it contains free
iodine. When enough hyposulphite is added to a solution of
this kind to combine exactly with the iodine, the blue color
disappears. Conversely, upon adding a solution of iodine to a
solution containing hyposulphite of sodium and a little starch,
the sensitive blue color of the iodide of starch will disappear
as fast as formed until all the thiosulphate has been changed to
tetrathionate, and then the first drop of iodine in excess will
change the solution to a permanent blue. The same thing Reaction be-
holds true as regards a solution containing free H2S, the reaction

being H2S+2l = 2HI + S. Proceed therefore as follows: Dis-
solve about I gramme of pure iodide of potassium in 300 c.c. iodine-
water, add 5 c.c. HC1, and then 25 c.c. of the bichromate solu-
tion, which will liberate a known amount of iodine. Drop in

70 ANALYSIS OF IRON AND STEEL.

standard- now the hyposulphite solution from a burette until the iodine
hyposui- nearly disappears, add a few drops of starch solution, and con-
tion. tinue the hyposulphite until the blue color fades out entirely.
The amount of iodine being known, the value of the hyposul-
phite solution is calculated from the reading of the burette. Now
standard- measure into a beaker with a carefully graduated pipette 25 c.c.
iodide1 so- of the hyposulphite solution, dilute to 300 c.c., add a few
drops of the starch solution, and drop, from a burette, standard
iodine solution until the blue color is permanent. The value
of the hyposulphite solution being known, that of the iodine
solution is readily calculated. An example will illustrate this :
illustration Suppose we find by titration that I c.c. of our bichromate solu-

of the cal-
culation of tion is equal to .00566 gramme metallic iron; then, as the

ofethVealsU0e-S reaction is 6FeCl2+ K2Cr2O7 + I4HC1 = 3Fe2Cl6 + 2KC1 + Cr2Cl6
+ 7H2O, I equivalent of K2Cr2O7 = 294.5 is equal to 6 equiva-
lents of Fe=336. Hence 336 : 294.5 = .00566 : .004961, or i
c.c. of the bichromate solution contains .004961 gramme K2Cr2O7,
and consequently 25 c.c. contain .124025 gramme K2Cr2O7. Then,
as we saw by the formula that 294.5 parts bichromate liberate
761.1 parts iodine, we have 294.5 : 761.1 =.124025 : .32052, or 25
c.c. bichromate solution liberate .32052 gramme iodine. We
now find that it requires 25.3 c.c. of the hyposulphite solution
to decolorize the solution made by adding 25 c.c. bichromate
solution to the iodide of potassium ; consequently each c.c. of
the hyposulphite contains enough NaHS2O3 to react with .01267
gramme iodine. We now measure out 10 c.c. of the hyposul-
phite solution, dilute it to 300 c.c., add a few drops of starch
solution, and find that it requires 20.1 c.c. of the iodide solution to
give the permanent blue color. Hence 20.1 c.c. = .1267 gramme
iodine, or I c.c. iodide solution contains .006303 gramme iodine.
As the reaction with H2S is H2S + 2! = 2HI + S, it requires 2
equivalents of iodine to decompose I equivalent of H2S, and the
proportion is 2! : S : : 253.7 : 32.06 : : .006303 : .000796, or I c.c.
iodine is equal to .000796 gramme sulphur.

RAPID METHODS FOR SULPHUR. n}

The standard solutions once ready, the actual determination
of sulphur in a sample is very simple. Measure 50 c.c. of a
solution of caustic soda, i.i sp. gr., free from sulphur, into the
first of the bottles D. The second need not be used, but it is
a good plan to keep a caustic potassa solution of nitrate of lead Details of
in it, and attach it after the other, to be certain that no H2S method,
escapes the caustic soda solution. Proceed with the determina-
tion as directed on page 61, and when finished wash the contents
of the bottle D into a beaker, dilute to 500 c.c., acidulate with
HC1, add a few drops of starch solution, and titrate with the
iodide solution. See exactly how much HC1 is required to
acidulate strongly 50 c.c. of the caustic soda solution, and this
amount can be added at once, so that no time need be lost in
testing the solution with litmus before titrating.

Mr. E. F. Wood,* of the Homestead Steel-Works, modifies
the method as follows : Pass the evolved gas into an ammoniacal
solution of sulphate of cadmium instead of caustic soda. Filter,
place the filter containing the precipitate of sulphide of cadmium
in a beaker containing cold water, add enough hydrochloric
acid to dissolve the precipitate, and titrate with iodine solution
as above described.

Mr. Wood thinks that this method has several advantages wood's
over that in which caustic soda is used to absorb the H2S. The J^1 c
hydrocarbon gases absorbed by the alkaline solution are gotten
rid of, and the error which their presence may produce is avoided;
the bulk of the precipitate is an indication of the amount of sul-
phur and a guide to the proper amount of hydrochloric acid to
use for its solution ; and when the sulphide of cadmium is
filtered off, only a small amount of hydrochloric acid is required,
and the generation of heat from the neutralization of the alkali
is avoided.

* Communicated to the author.

ANAL YSIS OF IRON AND STEEL.

DETERMINATION OF SILICON.

By Solution in HNO3 and HC1.

Dissolve 5 grammes of drillings in 40 c.c. HNO3 with the

precautions mentioned on page 65 ; although when silicon alone

Best strength is to be determined, HNCX of 1.2 sp. gr. may be used, when, in

of HN08

most cases, the solution of the drillings will be more rapid.

Remove the cover, evaporate the solution to dryness in the air-

bath, replace the cover, and raise the temperature of the bath

until the nitrate of iron is decomposed. Remove the beaker

from the air-bath, allow it to cool, add 30 c.c. HC1, and heat

gradually until all the ferric oxide is dissolved. Remove the

cover, and evaporate again to dryness in the air-bath, redissolve

in 30 c.c. HC1, dilute to about 150 c.c., and filter on an ashless

filter. Detach any adhering silica from the sides and bottom

of the beaker with a "policeman," and wash it out with cold

water. Wash the filter first with dilute HC1, and finally with

Testing water. Dry, and ignite in a platinum crucible until all the

Sio2wkh carbon is burned, weigh the residue in the crucible, moisten it

with water, add i-io drops H2SO4, and enough HF1 to dissolve

it completely, evaporate to dryness, ignite, and weigh. The

difference between the two weights is SiO2, which contains 47.02

By fusion per cent, of Si. In the absence of HF1, unless the SiO2 is per-

Na2co8 fectly white, fuse with 5 or 6 times the weight of Na2CO3, dis-

oratioT^" s°lve m water, acidulate with HC1, evaporate to dryness (in a

with HCI. platinum or porcelain dish, with the arrangement shown on page

20), redissolve in HCI and water, dilute, filter, wash, ignite, and

weigh. When the weight of Na2CO3 taken does not exceed

By treating 2 or 3 grammes, allow the crucible to cool after fusion, and then

crucible add to it gradually an excess of strong H2SO4, heating very

H*so4. slowly, until the mass is quite liquid and fumes of SO3 come off.

Allow it to cool, dissolve in water, filter, wash well, ignite, and

weigh.

DETERMINATION OF SILICON.

By Solution in HNO3 and H2SO4.

Drown * has suggested a method which, for pig-irons, has Brown's
come into very general use, and which is much more rapid than
the other method, and quite as exact. Treat I gramme of
borings in a platinum or porcelain dish with 20 c.c. HNO3, 1.2
sp. gr. When all action has ceased, add 20 c.c. of H2SO4 (equal
parts acid and water), and evaporate — using the arrangement
shown on page 20 — until copious fumes of SO3 are given off
Allow to cool, and dilute with 150 c.c. water; heat carefully
until all the sulphate of iron has dissolved, filter hot, wash first
with dilute HC1, i.i sp. gr., and then with hot water, ignite, and
weigh. Treat the contents of the crucible with H2SO4 and HF1,
evaporate to dryness, ignite, and weigh again. The difference
between the two weights is SiO2.

By Volatilization in a Current of Chlorine Gas.

As almost all steels and irons contain slags of various com- presence of
positions, it must be understood that the SiO2 obtained by the ^onTnd
methods above given is the total SiO2, comprising any SiO2 that steeK
may be present m the admixed slag, as well as that formed
from the Si present in the metal. The volatilization method Separation
separates the two. The process suggested by Drown,f and sio^
worked out independently two years later by Watts,! is as fol-
lows : Fig. 49 shows the general arrangement of the apparatus. Description
The large flask contains binoxide of manganese in lumps. The
bottle above it contains strong common HC1, which runs into
the flask through a siphon-tube extending almost to the bottom.
The flask stands in a dish containing water, which can be
heated by the burner under the tripod. The evolution-tube
from the flask has a stopcock, and connects with the three
bulb-tubes on the stand, the first containing water, the second

* Jour. Inst. Min. Engineers, vii. 346. f Ibid., viii. 508.

% Chem. News, xlv. 279.

ANAL YSIS OF IRON AND STEEL.

DETERMINATION OF SILICON. j^

pumice-stone, and the third pumice saturated with strong H2SO4.
The outlet-tube from the latter leads into the porcelain or glass
tube in the furnace. This tube contains small lumps of char- Purification
coal or gas carbon, kept in position by loosely-fitting plugs of fr0mo.
asbestos,' and occupying about 8 inches (200 mm.) in the middle
of the tube. The outlet-tube from this connects with the
drying-tubes on the second stand, which contain pumice moist-
ened with strong H2SO4. The outlet from the second drying-
tube connects with the glass combustion-tube, which leads
through the second furnace, and is bent at a right angle where
it is connected with the large tubes, half filled with water. The
apparatus being in order, * start a slow current of chlorine Details of
through the apparatus by blowing HC1 from the bottle into the method.
flask and filling the dish in which the latter stands with water.
Light a low light under the dish, and open the stopcock wide
enough to allow a very slow current to bubble through the
bulbs. Light the burners of the first furnace so that the tube is
heated to dull redness. When the apparatus is full of chlorine,
weigh i gramme of pig-iron, or 3 grammes of steel, into a
porcelain boat about 3 inches long, distributing the drillings
evenly along the bottom of the boat. Remove the stopper at
the rear end of the second tube and insert the boat to about
the centre. Replace the stopper, and continue the current of
chlorine in the cold for ten or fifteen minutes to make sure that
no oxygen remains in the tube, then light the burner under the
forward end of the boat. The heat must be just sufficient to

volatilize the ferric chloride, which should condense in the
cooler part of the tube, and the current of gas should be slow
enough to prevent any ferric chloride from being carried for-
ward into the water-tubes or any loss of carbon from the boat.

* All the stoppers used should be of rubber coated with paraffine on the ends, or
of asbestos, and where glass tubes are joined together with rubber the ends of the
glass tubes should be brought into close contact.

7 6 ANALYSIS OF IRON AND STEEL.

When the fumes of ferric chloride begin to come off more
slowly, light the next burner, and continue until all the burners
under the boat are lighted, maintaining the heat until the fumes
of ferric chloride cease. The tube for the entire length occupied
by the boat should be at a dull red heat. Should the condensed
ferric chloride at any time choke the tube so as to prevent the
passage of the gas, heat that part of the tube gently with a
spirit-lamp, so as to drive the ferric chloride a little farther
along the tube. When the fumes of ferric chloride are no longer
given off from the boat, the operation may be considered finished.
Turn out the lights under the tube containing the boat, remove
the stopper, and draw out the boat, which now contains the
carbon, the slag, and the greater part of the manganese (as
Residue in Mnd2) which were contained in the iron or steel. This residue

boat avail-
able for may be used for the determination of the carbon or the slag,

donofc as will be shown farther on. If another determination is to be
>ag' made, another tube may be substituted for the one which con-
tained the boat, and the analysis carried out in the manner
described above. If not, put out all the lights, close the
stopcock, and withdraw the combustion-tube with the water-
tubes. Remove the stoppers from the latter, and pour the con-
tents of these tubes into a platinum dish containing a small
amount of an aqueous solution of sulphurous acid, to prevent
the chlorine in the solutions from acting on the platinum.
Rinse the tubes into the dish, and if any silica has separated
out and adheres to the water-tubes or to the end of the com-
bustion-tube, loosen it with a " policeman" and wash it into the
dish. Add 5 c.c. strong H2SO4, evaporate to dryness, and heat
until fumes of SO3 are given off. Allow the dish to cool, add
100 c.c. cold water, and filter off on a small ashless filter any
SiO2, which burn and weigh as such. Calculate to Si. The
Separation filtrate from the SiO2 will contain any TiO2 which may have

from TiO2.

been in the metal and which can be 'determined, as will be
shown farther on. Silicon and titanium are volatilized as

RAPID METHOD FOR SILICON.

chlorides, SiCl4 and TiCl4, under the conditions shown above,
and decomposed by water thus: SiCl4 + 2H2O = 4HC1 + SiO2
and TiCl4 + 2H2O = 4HC1 + TiO2.

tion by
H,0.

Rapid Method for Determination of Silicon. (S. Alfred

Ford.*)

At the Edgar Thomson Steel-Works the molten pig-metal
is taken directly from the furnaces to the converters, and it is
generally necessary to determine the amount of silicon in the
pig-iron as a guide in blowing the metal. To get the sample Method of
for analysis, a small ladle is dipped into the iron as it runs from ^fe
the furnace, and a small quantity of molten iron is taken. The
ladle is then held about three feet above a bucket of water, and
the molten metal drooped into the water, at the same time giving

the ladle a circular motion over the bucket. This will cause the Appearance

of shot de-
iron to form in globules, more or less round according to the pending

amount of silicon contained in the iron. Thus, with iron which °° si"™
contains 2 per cent, of silicon or more, the globules will be
almost perfectly round, concave on the upper surface, and gen-
erally from j{ inch (6 mm.) to ^ inch (9 mm.) in diameter;
while if the iron be low in silicon, the shot or drops will be
very small, flat, and irregular in shape, and if the iron be very
low in silicon, as is the case with spiegel and ferromanganese,
the shot will be elongated and have tails sometimes *^ inch
(6 mm.) in length. In fact, a close observer can soon judge very
closely as to the amount of silicon from the condition of these
shot or drops. The next step in the process is to take the shot
from the bucket and place them for a minute in the ladle which
has been used to dip up the molten iron. The ladle, being hot,
will dry the shot almost instantly. The shot are then placed Pulverizing
in a large steel mortar (Fig. 7, page 17) and crushed. The ple.
crushed shot are then sifted with a fine sieve, and .5 gramme

* Prepared by Mr. Ford for this volume.

78 ANAL YSIS OF IRON AND STEEL.

Determina- of the fine siftings are placed in a platinum evaporating-dish, 10

tion of the

Si. c.c. HC1, 1.2 sp. gr., are then added, and the dish covered with

a watch-glass. The dish is then placed over a light, and the iron
dissolved ; as soon as solution takes place, which requires about
one minute, as the particles of iron are so small, the watch-
glass is removed and the solution evaporated to dryness as
rapidly as possible over a naked light ; as soon as dry, not even
waiting for the dish to cool, dilute HC1 is dropped on the
chloride of iron, and as soon as all the sesquioxide of iron
(which may have been formed by the decomposition of the chlo-
ride) is dissolved, water is added. The contents of the dish
are then poured on a filter, to which is attached a pump, filtered,
and washed. The filter and its contents are then placed in a

Burning c weighed platinum crucible, placed over a blast-lamp ; as soon
of o. as the filter-paper is burned off, the crucible is turned on its
side, the lid removed, and a small jet of oxygen is driven very
gently into the crucible. As soon as what little carbon there
is in the precipitate is burned off, the crucible is cooled and
weighed, and the amount of silicon calculated from the weight
of the silica in the crucible.

Time re- By this method the amount of silicon in a pig-iron can be

quired for

determi- determined in twelve minutes from the time the ladle is put

nation

Of si. into the molten iron, and it gives results close enough for prac-
tical purposes.

DETERMINATION OF SLAG AND OXIDES.

Presence of A certain amount of slag and oxide of iron is always present

and steel, in puddled iron as a mechanical admixture. It is also found,
as a general thing, in basic steel, and the presence of slag in
steel made by the acid process, as well as in pig-iron, is not
unusual. The easiest method for the determination of these
substances is by solution in iodine, as suggested by Eggertz.

DETERMINATION OF SLAG AND OXIDES.

By Solution in Iodine.

Weigh 5 grammes of borings free from lumps into a No. 2 Details of
Griffin's beaker. Stand the beaker, carefully covered with a method,
watch-glass, in a dish filled with scraped ice or snow, so that the
bottom and sides of the beaker half-way up shall be in contact
with it. Pour over the iron in the beaker 25 c.c. of ice-cold
boiled water, and stir until all the air in the borings has escaped.
Add gradually 28 or 30 grammes of resublimed iodine,* stirring
occasionally, until all the iodine has dissolved. Keep the beaker
constantly surrounded by ice, and add the iodine slowly enough
to prevent any rise in the temperature of the solution. Stir the
solution frequently until the iron is perfectly dissolved, which
will take several hours; then add 100 c.c. cold boiled water,
allow the insoluble matter to settle, and decant the supernatant
fluid on a small ashless filter. Wash the insoluble matter several
times, by decantation, with cold water, then add to it a little insuring

total solu-

water, with a few drops of HC1, and observe whether any hydro- tionofFe.
gen is disengaged. If none can be perceived, the metallic iron
may be considered entirely dissolved ; but if gas is given off,
the opposite is the case. In either event, quickly decant the
acidulated water on the filter, and if any metallic iron remains,
add a very little water and some iodine to dissolve the iron
entirely. Then transfer the insoluble matter, consisting of
graphite, carbonaceous matter, slag, oxide of iron, and some Separation
silica, to the filter, wash the filter once with very dilute HC1
(i acid to 20 water), and finally with cold water, until the filtrate
is free from iron. Unfold the filter, and with a fine jet wash
the insoluble matter off into a small platinum or silver dish.
Evaporate almost to dryness, add 50 c.c. solution of caustic
potassa, sp. gr. i.i, and boil five or ten minutes. Decant the
liquid on a very small ashless filter, repeat the boiling with

* Page 41.

3O ANALYSIS OF IRON AND STEEL.

fresh caustic potassa, transfer the insoluble matter to the filter,
and wash well with hot water. Wash once with dilute HC1
(i acid to 20 water), and finally with hot water, until the filtrate
gives no precipitate with a solution of nitrate of silver. Dry,
ignite, and weigh as Slag and Oxide of Iron.

Instead of using iodine directly for the solution of the iron,
Use of iodine a solution of iodine in iodide of iron, as suggested by Eggertz,*

in iodide of

iron as a may be used to great advantage, as it affords a ready method
for getting rid of the impurities usually present in resublimed
iodine. Treat 5 grammes of iron (as free as possible from
silicon) with 25 grammes of iodine, and, when the solution is
complete, add 30 grammes more of iodine, which will dissolve
in the iodide of iron in a few minutes. Dilute to 50 c.c. with
cold boiled water and filter through a washed filter. Add the
filtrate at once to 5 grammes of the weighed sample, and, after
solution is complete, proceed as directed above.

By Volatilization in a Current of Chlorine Gas.

Proceed exactly as in the method for the determination of

silicon (pages 74 et seq.} until the boat is withdrawn from the

washing out combustion-tube. Wash the contents of the boat into a small

chlorides, beaker with a jet of cold water, and filter on a small ashless

filter. The water dissolves any soluble metallic chlorides, MnCl2,

CaCl2, etc., which are not volatile at a low red heat, and the

insoluble matter in the filter consists of slag and carbon. Burn

off the carbon and weigh the residue as Slag and Oxides. Or,

Using coun- if the carbon has been determined by another operation, filter

terpoised

filters. the carbon and slag on a counterpoised filter j or on a Goocn
crucible, dry at 100° C., and weigh as Carbon, Slag, and Oxides;
by subtracting the weight of the carbon the difference is Slag
and Oxides.

* Jern-Kontorets Annaler, 1 88 1, p. 301, and Chem. News, xliv. 173.
f See page 27.

DETERMINATION OF PHOSPHORUS. OF QT

™

DETERMINATION OF PHOSPHORUS.

For the determination of phosphorus in iron and steel but
two methods are in general use, either of which, properly
carried out, will give extremely accurate results. Some chemists
prefer one method, some the other, while a combination of the
two is sometimes used. The two general methods are known
respectively as the Acetate Method and the Molybdate Method. Methods in
There are innumerable variations in the details, especially of
the latter method, but any departure from what might be
termed the standard instructions should never be attempted by
any but a very experienced analyst.

The Acetate Method.

The essential parts of this method were suggested by Fre-
senius,* the changes and improvements in details being the
work of many chemists.t

Treat 5 grammes of drillings in a No. 4 Griffin's beaker with Detailsof

the acetate

80 c.c. HNO3 (1.2 sp. gr.), and, when violent action has ceased, method.

add 10 c.c. strong NCI. Evaporate the solution to dryness in the

air-bath, replace the cover, and heat until the nitrate of iron is

nearly all decomposed. Cool, add 30 c.c. HC1, heat gradually

until the oxide of iron is dissolved, and evaporate to dryness again

in the air-bath. Cool, dissolve in 30 c.c. HC1, dilute, and, in steels

or puddled iron, when silicon is to be determined, filter, and treat When si is

to be de-

the insoluble matter as directed for the determination of Si, page 72.

In the case of pig-irons which may contain titanium, filter,
and keep the residue of graphite, silica, etc., for treatment, as
directed farther on, " when titanium is present."

In the case of steels, when silicon is not to be determined when si is

not to be

in this portion, the solution need not be filtered at all, but may deter-
be diluted at once to about 250 c.c.

* Jour, fiir Pr. Ch., xlv. 258.

f Tenth Census of the U. S., vol. xv. " Iron Ores of the U. S.," p. 523.

present.

32 ANALYSIS OF IRON AND STEEL.

In any case, heat the filtered or unfiltered HC1 solution
nearly to boiling, remove the beaker from the light, and add
gradually from a small beaker a mixture of 10 c.c. NH4HSO3*
and 20 c.c. NH4HO, stirring constantly. The precipitate, which
forms at first, redissolves, and when all but about 2 or 3 c.c.
of the NH4HSO3 solution has been added, replace the beaker
Deoxidiz- over the light. If at any time while adding the NH4HSO3
solution, solution the precipitate formed will not redissolve even after
vigorous stirring, add a few drops of HC1; and, when the solu-
tion clears, continue the addition, very slowly, of the NH4HSO3.
After replacing the beaker on the light, add to the solution
(which should smell quite strongly of SO2) NH4HO, drop by
drop, until the solution is quite decolorized, and until finally a
slight greenish precipitate remains undissolved even after vig-
orous stirring. Now add the remaining 2 or 3 c.c. of the
NH4HSO3 solution, which should throw down a white precipi-
tate, which usually redissolves, leaving the solution quite clear
and almost perfectly decolorized. Should any precipitate remain
undissolved, however, add HC1, drop by drop, until the solution
clears, when it should smell perceptibly of SO2. If the reagents
are used in exactly the proportions indicated, the reactions will
take place as described, and the operations will be readily and
quickly carried out. If the solution of NH4HSO3 is weaker
than it should be, of course the ferric chloride will not be
reduced, and the solution, at the end of the operation described
above, will not be decolorized and will not smell of SO2. In
this case add more of the NH4HSO3 (without the addition of
NH4HO) until the solution smells strongly of SO2, then add
NH4HO until the slight permanent precipitate appears, and
redissolve it in as few drops of HC1 as possible. The solution
being now very nearly neutral, the iron in the ferrous condition,
and an excess of SO2 being present, add to the solution 5 c.c.

* See page 44.

DETERMINATION OF PHOSPHORUS. 3^

of HC1 to make it decidedly acid and to insure the complete
decomposition of any excess of the NH4HSO3 which may be
present. Boil the solution,* while a stream of CO2 passes Boiling off
through it, until every trace of SO2 is expelled, then pass a ^^
current of H2S through it for about fifteen minutes to precipi-

FIG. 50.

tate any arsenic which may be present, and finally allow the
solution to stand in a warm place until the smell of H2S has
disappeared, or, better, pass a current of CO2 through the

* By passing a current of CO2 through the boiling solution the SO2 is soon ex-
pelled, and the operation requires no watching.

ing the As.

ANALYSIS OF IRON- AND STEEL.

solution, which will expel the H2S in a few minutes. The
arrangement, Fig. 50, is convenient for this purpose. Filter
from any As2S3, CuS, S, etc., into a No. 5 beaker, wash with
cold water, and to the filtrate add a few drops of bromine-water,
and cool it by placing the beaker in cold water. To the cold
solution add NH4HO from a small beaker very slowly, and
finally drop by drop, with constant stirring. The green pre-
cipitate of ferrous hydrate which forms at first is dissolved by
stirring, leaving the solution perfectly clear, but subsequently,
drate. although the green precipitate dissolves, a whitish one remains,
and the next drop of NH4HO increases the whitish precipitate
or gives it a reddish tint, and finally the greenish precipitate
remains undissolved even after vigorous stirring, and another
drop of NH4HO makes the whole precipitate appear green.
If before this occurs the precipitate does not appear decidedly
red in color, dissolve the green precipitate by a drop or two
of HC1, and add a little bromine-water (i or 2 c.c.), then add
NH4HO as before, and repeat this until the reddish precipitate
is obtained, and then the green coloration as described above.
Dissolve this green precipitate in a very few drops of acetic acid
(sp. gr. 1 .04), when the precipitate remaining will be quite red in
color, then add about I c.c. of acetic acid, and dilute the solu-
tion with boiling water, so that the beaker may be about four-
Filtering and fifths full. Heat to boiling, and when the solution has boiled
riieVr"8 one minute, lower the light, filter as rapidly as possible through
a 5^-inch (i4O-mm.) filter, and wash once with hot water.
The filtrate should run through clear, but in a few minutes it
will appear cloudy by the precipitation of the ferric oxide, which
has been formed by the exposure of the filtered solution to the
Precautions, air. The points to be observed are the red color of the precipi-
tate and the clearness of the solution when it first runs through.
Ferric phosphate being white, the red color of the precipitate
shows that enough ferric salt was present in the solution to
form ferric phosphate with all the phosphoric acid, and enough

DETERMINATION OF PHOSPHORUS. 35

more to color the ferric phosphate red with the excess of ferric
oxide.

When the precipitate has drained quite dry, pour about 15 c.c.
of HC1 into the beaker in which the precipitation was made,
warm it slightly so that the acid may condense on the sides and Solution of

the prccip"

dissolve any adhering oxide, wash off the cover into the beaker, Hate.
add about 10 c.c. of bromine-water, pour this on the filter con-
taining the precipitate, allowing it to run around the edge of the
filter, and let the solution run into a No. I Griffin's beaker.
Wash out the beaker once or twice, and then wash the filter
well with hot water. If the acid in the beaker is not sufficient
to dissolve the precipitate completely, drop a little strong acid
around the edge of the filter before washing it with hot water.
The scaly film of difficultly soluble oxide which sometimes forms cause of
on boiling the acetate precipitate is caused by the presence of cuitiy sol.
too much acetate of ammonium, but when the instructions given
above are carefully carried out it never appears. Evaporate
the solution in the small beaker nearly to dryness to get rid
of the excess of HC1, add to it a filtered solution of 5 or 10
grammes of citric acid (according to the size of the precipitate
of Fe2O3, etc.) dissolved in 10 to 20 c.c. of water, then 5 to
10 c.c. of magnesia-mixture and enough NH4HO to make the
solution faintly alkaline. Stand the beaker in cold water, and
when the solution is perfectly cold, add to it one-half its volume
of strong NH4HO and stir it well. When the precipitate of Predpita-
Mg2(NH4)2P2O8 has begun to form, stop stirring, and allow it to th°Mg,
stand in cold water for ten or fifteen minutes, then stir vigorously ^4)s
several times at intervals of a few minutes, and allow it to stand
overnight. Filter on a small ashless filter, and wash with a
mixture of 2 parts of water and I part of NH4HO containing
2.5 grammes of NH4NO3 to 100 c.c.

Dry the filter and precipitate, and ignite them at a very low Filtering

and burn-

temperature at first so as to carbonize the filter without decom- ingthe
posing the precipitate, which may then be readily broken up tate.

ANALYSIS OF IRON AND STEEL.

Treatment
soluble

Treatment

with a platinum wire. Raise the heat gradually, and finally
ignite at the highest temperature of the Bunsen burner. When
the precipitate is perfectly white, cool and weigh. Then fill
the crucible half full of hot water, add from 5 to 20 drops of
HC1, and heat until the precipitate has dissolved. Filter off on
another small, ashless filter any SiO2 or Fe2O3 that may remain,
ignite, and weigh. The difference between the two weights is
the weight of Mg2P2O7, which, multiplied by 0.27836, gives the
weight of P.

When Titanium is Present.

When a solution of ferric chloride containing TiO2 and P2O5
is evaporated to dryness, a compound of TiO2,P2O5 and Fe2O3 is
formed, completely insoluble in dilute HCL*

Iron ores and pig-irons containing TiO2 require, therefore, a
somewhat different method of treatment from that given above.

Dry and ignite the residue of graphite, silica, etc., from the
solution of the pig-iron, so as to burn off all the carbon. Moisten
this residue with cold water, add 5 to 10 drops of H2SO4 and
enough HF1 to dissolve the silica, and evaporate until fumes
of SO3 are given off. While this is going on, proceed with the
deoxidation of the filtrate as described above, but when the SO2
has been driven off do not pass H2S through the solution, but
cool it, and proceed with the acetate precipitation. Instead of
dissolving the precipitate, after washing it as described above, dry
the filter and precipitate in the funnel, being careful not to heat
it so as to scorch the filter. Clean out any of the precipitate
which may have adhered to the sides of the beaker in which the
precipitation was made, by wiping it with filter-paper, and dry
this paper with the filter and precipitate.

When the precipitate is quite dry, transfer it to a small por-
celain mortar. The precipitate may be readily detached from

* Published in Report on Methods employed in the Analysis of the " Iron Ores,"
Tenth Census U.S., vol. xv. p. 512. I first noted this fact in 1878.

DETERMINATION OF PHOSPHORUS. g*

the filter by rubbing the sides of the latter together over a large
piece of white, glazed paper, so that any little particles that fall
out may be seen. Roll up the filter with the bits of paper which
were used to wipe out the beaker, wrap a piece of platinum
wire around it, burn it on the lid of the crucible in which the
graphitic residue was treated, and transfer the ash to the mortar.
Grind the precipitate and ash with 3 to 5 grammes of Na2CO3 Fusion of the

precipi-

and a little NaNO3, and transfer it to the crucible containing tate.
the residue which was treated by HF1 and H2SO4. Clean the
mortar and pestle by grinding a little more Na2CO3, and add
this to the other portion in the crucible. Fuse the whole for
half an hour or more, cool, dissolve the fused mass in hot water,
filter from the insoluble Fe2O3, etc.,* acidulate the filtrate with
HC1, add a few drops of NH4HSO3, boil off all smell of SO2,
and pass H2S through the hot solution to precipitate any arsenic
that may be present. Pass a current of CO2 through the solu- Precipita-
tion to expel the excess of H2S, filter off the As2S3, and to the AS.
filtrate add a sufficient amount of Fe2Cl6 solution to combine
with all the P2O5 as Fe2(PO4)2 and leave a slight excess. Add
a slight excess of NH4HO, which should throw down a red
precipitate, while- the solution is alkaline to test-paper ; then add
acetic acid to slightly acid reaction, boil, and filter off the
Fe2(PO4)2 and Fe2O3, and wash with hot water. Dissolve the
precipitate in HC1, allow the solution to run into a small beaker, Predpita-

. , t . tion of the

evaporate until the solution is syrupy, add citric acid and mag- Mg2

nesia-mixture, and precipitate the Mg2(NH4)2P2O8 as described pj^

above. Unless the amount of phosphorus is very small, a second

fusion of the insoluble residue of Fe2O3, etc., is necessary. The Necessityfor

two filtrates can then be added together, acidulated with HC1,

and the remainder of the process carried out as directed above.

To avoid the fusion of the acetate precipitate with Na2CO3, which

* This Fe2O3, etc., contains all the titanium that was in the pig-iron as titanate of
soda, and must be kept for the estimation of that element when it is to be determined.

88 ANALYSIS OF IRON AND STEEL.

is always troublesome, the method for the determination of
phosphorus may be modified (in many cases with advantage,
and generally when titanium is not to be estimated) as follows :
After filtering off the insoluble matter, graphite, silica, etc., ignite
it, burn off the graphite, and treat the residue with HF1 and
H2SO4, evaporate down until the excess of H2SO4 is driven off,
and fuse with Na2CO3. Treat the fused mass with water, and
filter. Acidulate the filtrate with HC1, and add it to the main
Method to solution, which has been deoxidized in the mean time with bisul-
phite of ammonium. Expel the last traces of SO2 from the
umted filtrates by boiling and passing a current of CO2 through

acetate £he solution, as previously directed. If the solution remains clear,

precipi-

tate- pass H2S through it, and filter off the precipitated sulphides.

Cool the solution, and make the acetate precipitation as directed

Tendency of on page 84. The only danger to be apprehended now is the

TiO2 to

separate tendency of titanic acid to separate out and carry phosphoric
acid with it when in the evaporation of the HC1 solution of the
acetate precipitate the liquid becomes concentrated. To avoid
this, the evaporation must be watched very carefully, and citric
acid added as soon as the titanic acid begins to separate. Then,
if the separation has not proceeded too far, the phosphoric acid
may be precipitated in the usual way. If, however, the separation
of titanic acid is not checked in time, proceed with the evapo-
ration as directed on page 85, add 5 c.c. strong HC1, and warm
gently. The solution will nearly always clear, but if it does
not, then add citric acid and a slight excess of ammonia, and
filter. Stand the filtrate aside, burn off and fuse the precipitate
with Na2CO3, dissolve in. water, filter, acidulate the filtrate with
HC1, add a little Fe2Cl6 solution, a slight excess of ammonia,
and acidulate with acetic acid. Boil, filter off the precipitate
of phosphate and oxide of iron, dissolve in a little HC1, allow
the solution to run into a small beaker, evaporate down, and add
it to the ammoniacal filtrate from the separated titanic acid
obtained above. Add excess of magnesia-mixture, and precip-

DETERMINATION OF PHOSPHORUS.

itate the phosphoric acid in the usual way. When the solution other

sources of

becomes cloudy after deoxidation with NH4HSO3, and remains error.
so after acidulating with HC1, proceed as directed above, but
dry, and ignite the filter containing the precipitate by H2S and
that on which the acetate precipitate was filtered, fuse with
Na2CO3, treat with water, filter, acidulate with HC1, pass H2S
through the solution, filter, add a little Fe2Cl6 solution, and pre-
cipitate by ammonia and acetic acid. Add the solution of this
precipitate, after filtering it off, to the solution of the main
acetate precipitate, and proceed as before.

Instead of adding citric acid and magnesia-mixture to the Removing
solution of the acetate precipitate, Fresenius,* and afterwards Fes before

Spiller,t advised the method of adding citric acid, excess of
ammonia, and sulphide of ammonium, filtering off the precipi-
tated sulphide of iron, and, after evaporating to small bulk,
adding magnesia-mixture and ammonia. When the bulk of the
iron precipitate is not too great, this is quite unnecessary, for Shown to be
many determinations have shown that with an excess of mag- sary-
nesia-mixture, ammonium magnesium phosphate is absolutely
insoluble in both citrate of iron and ammonium and citrate of
aluminium and ammonium.

The precipitate is also insoluble in ammonia- water (i part
of NH4HO to 2 parts of water).

The Molybdate Method.

Svanberg and StruveJ first discovered the reaction on which
this method is based, and Sonnenschein § first used it quantita-
tively. Weigh 5 grammes of drillings into a No. 4 Griffin's
beaker, and add, with the proper precautions (page 65), 40 c.c.
strong HNO3. Instead of using HC1 to hurry the solution, it solution.
is better, when the action slackens, to add water very cautiously

* Jour, fur Pr. Chem., xlv. 258. f Jour. Chem. Soc. (2), iv. 148.

J Jour, fur Pr. Chem. xliv. 291. g Jour, fur Pr. Chem., liii. 339.

ANALYSIS OF IRON AND STEEL.

from time to time until the metal is completely dissolved. Evapo-
rate to dryness in the air-bath, replace the cover, and heat for
one hour at a temperature of about 200° C. in order to decom-

Destroying pose all the carbonaceous matter,* otherwise the precipitation

bonaceous of the phospho-molybdate will be incomplete. Allow the beaker

to cool, dissolve the precipitate in 30 c.c. HC1, evaporate to dry-

ness to render the silica insoluble, redissolve in 30 c.c. HC1,

Removal of and evaporate carefully until the excess of HC1 is driven off,
shaking the beaker from time to time to prevent the forma-
tion of a crust of dry chloride of iron. Cool the beaker, and
dilute the solution with twice its volume of cold water. Filter
on a small, washed German filter, 3-inch (7 5 -mm.), or on the
Gooch crucible. In the latter case the precipitation of the
phospho-molybdate may be made in the small flask into which
the solution is filtered. The washing should be done with cold
water after dropping a little dilute HC1 around the edge of the

Volume of filter. The filtrate and washing should not exceed 50 or 60 c.c.
aon. in volume. Add to the solution 50 to 100 c.c. molybdate solu-

tion,f heat it to 40° C. in a water-bath carefully kept at this

ture of the

solution, temperature, and allow it to stand in the bath for about four
hours. Filter on a small, washed filter, and wash thoroughly
with dilute molybdate solution (i part of solution to I part of
water) until a drop of the filtrate gives no reaction for iron
with ferrocyanide of potassium. Stand the filtrate aside in a
warm place to see whether any further precipitation of phospho-
Soiutionof molybdate of ammonium takes place; if it does, it must be
filtered off and treated like the main precipitate. Pour 2 or 3^
c-c- strong NH4HO on the precipitate, stir it up with a fine jet
of hot water, and allow the solution to run into the flask or
beaker in which the precipitation of phospho-molybdate was

* In 1877 I discovered the necessity for destroying the carbonaceous matter, and
communicated the fact to Hunt and Peters, who mentioned it in the Metallurgical
Review, vol. ii. p. 365.

f See page 59.

DETERMINATION OF PHOSPHORUS. QJ

made. When it has all run through the filter, replace the flask
or beaker by a small beaker of a little over 100 c.c. capacity,
remove any phospho-molybdate that may have adhered to the
sides of the original flask or beaker, by means of the ammoni-
acal filtrate, and then pour this back on the filter and allow it
to run through into the small beaker. Wash out the beaker or
flask with hot water and pour it on the filter with the addition
of a little more NH4HO. Unless the precipitate of phospho-
molybdate is very large, this amount of NH4HO should dis-
solve it, and a very little more washing should be sufficient.
If the precipitate is very large, it may be necessary to use more Volume of
NH4HO and more wash-water, but under all circumstances the niacaiso-
amount of NH4HO and of wash-water should be as small as is
consistent with perfect solution of the precipitate and thorough
washing of the beaker and filter. When the precipitate is
small, the filtrate and washings should amount to about 25 c.c.
Neutralize the solution with strong HC1 ; if the yellow phospho- ^
molybdate begins to precipitate, add NH4HO until it redissolves,
and if there should remain a flocculent white precipitate, prob-
ably silica, after the solution is quite alkaline, filter it off.
Then to the cold alkaline liquid add, very slowly, 10 c.c.
magnesia-mixture, stirring constantly, and after the magnesia-
mixture is all in, add one-third the volume of the solution of P2°8'
strong NH4HO and stir vigorously. It is well to stand the
beaker in cold water and stir the solution several times after
the precipitate has begun to crystallize out. After standing
about four hours, it may be filtered off on a very small ashless
filter and washed with dilute ammonia- water (i part NH4HO to
2 parts water) containing 2.5 grammes nitrate of ammonium to
the 100 c.c. Dry, ignite very carefully to burn off the carbon- Filtration
aceous matter, and finally heat for ten minutes over the blast-
lamp to volatilize any molybdic acid that may have been
precipitated with the Mg2(NH4)2P2O8, cool, and weigh. Fill the
crucible half full of hot water, add 5 to 20 drops HC1, and

ANALYSIS OF IRON AND STEEL.

date.

heat for a few minutes to dissolve the Mg2P2O7. Pour the
contents of the crucible on a small ashless filter, wash, ignite,
and weigh the small residue that may remain undissolved. The
difference between the two weights is the weight of Mg2P2O7,
which contains 27.836 per cent, phosphorus.

Direct Many chemists, following Eggertz,* prefer to weigh the

of the yellow phospho-molybdate direct instead of dissolving it and
precipitating as Mg2(NH4)2P2O8. In this event take I gramme
of the drillings and proceed exactly as directed above, but use
only about one-third the amount of HNO3 and HC1 for the
solution. Before adding the molybdate solution, the volume of
the filtrate from the silica should amount to only about 25 c.c.
Add 50 c.c. of the molybdate solution, allow it to stand four
hours at a temperature of 40° C., and filter off the precipitated
phospho-molybdate on a Gooch crucible; wash first with dilute
molybdate solution, and finally with water containing I per
cent, of HNO3, dry in an air-bath heated to 120° C., and weigh
as (NH4)3uMoO3PO4 (approximate formula), containing 1.63 per
cent, of phosphorus. In the absence of a Gooch crucible, use
counterpoised filters f for weighing the phospho-molybdate. The
points of special importance are :

First, the necessity for destroying all the carbonaceous matter
by heating the nitric acid solution, after evaporation, to a suffi-
ciently high temperature to effect this with certainty.

Second, the avoidance of an excess of HC1 in the final solu-
tion before precipitating by molybdate solution.

Third, when the phospho-molybdate is weighed directly, the
necessity for rendering the silica insoluble.

Fourth, the danger of heating the solution above 40° C.
after adding the molybdate solution, as arsenic, when present,
precipitates with the phosphorus if the solution is heated to a
higher temperature.

Precautions
necessary.

* Jour, fur Pr. Chem., Ixxix. 496.

f See page 28.

DETERMINATION OF PHOSPHORUS.

Fifth, the danger of causing a precipitation of molybdic acid
with the phospho-molybdate by heating the solution to a tem-
perature approximating 100° C.

Some chemists prefer to drive off the HC1 entirely by adding variations
HNO3 to the hydrochloric acid solution, and boiling down detafli.
nearly to dryness once or twice before filtering off the silica.

Others, after filtering off the silica, add NH4HO until a slight
permanent precipitate appears, then the molybdate solution, which
is sufficiently acid to redissolve the slight precipitate of ferric
hydrate, and leave the solution quite clear, with the exception
of the precipitate of phospho-molybdate. Others supersaturate
the hydrochloric acid solution with NH4HO, and redissolve with
the least possible amount of HNO3 before adding the molyb-
date solution. Many of these are matters of personal preference,
but the safest plan for the beginner is to follow the instructions
first given until he has sufficient knowledge and experience to
judge of the value of these variations, or to invent some for
himself.

The Combination Method.

Riley* was the first to suggest the precipitation of phos- .
phorus as phospho-molybdate, preceded by a separation of the
phosphoric acid from the mass of the ferric chloride by deoxi-
dation and precipitation by the acetate method. This method
was worked out afterwards by A. Wendel, of the Albany and
Rensselaer Steel Company, S. Peters, of the Burden Iron Com-
pany, and J. L. Smith.f

Proceed as directed for the determination of phosphorus by Details

of the

the Acetate Method, using I gramme of borings and proper- method,
tional amounts of reagents until having dissolved the acetate
precipitate in HC1, evaporate to dryness, redissolve in a very
little HNO3, dilute to 20 c.c. with water, add a slight excess
of NH4HO, redissolve the precipitated ferric oxide in HNO3,

* Jour. Chem. Soc., 1878, vol. i. p. 104. f Chem. News, xlv. 195.

94 ANAL YSIS OF IRON AND STEEL.

and add 30 c.c. molybdate solution. Heat to 40° C. for an
hour, filter, wash with water containing I per cent, of HNO3,
dry, and weigh.

When Titanium is Present.

When phosphorus is determined in pig-irons containing tita-
nium, burn off the residue of carbon, silica, etc., treat it with
HF1 and H2SO4, evaporate, and heat until the greater part of the
H2SO4 is driven off. Fuse with 2 or 3 grammes of carbonate
of sodium, dissolve in water, filter, acidulate the filtrate with
HNO3, add 50 c.c. molybdate solution, and heat to 40° C. for
four hours. Filter, wash, and add this precipitate to the one
obtained in the filtrate from the carbon, silica, etc. If any slight
insoluble matter should remain on the filter upon dissolving in
NH4HO the phospho-molybdate obtained in the filtrate from the
carbon, silica, etc., burn it, fuse it with carbonate of sodium, and
test it also for phosphorus.

As remarked above, page 92, the formula given for the dried
Variable phospho-molybdate of ammonium is approximate only. The

composi-

don of the composition of the salt seems to vary very much, the percentage
mo°yb-°~ °f phosphorus in it being given by various authorities from
1.27 to 1.75. It seems to depend upon various circumstances,
such as the presence or absence of HC1 in the solution, the
degree of acidity, the temperature at which the precipitation is
effected, the length of time the solution stands before the pre-
cipitate is filtered off, the size of the precipitate, the state of
concentration of the solution, and even the amounts of the iron
and ammonium salts present.
The precau- This fact must be borne in mind when the phosphorus is

tions it ne-
cessitates, determined by direct weighing of the phospho-molybdate, and

every effort must be used to effect the precipitations always
under as nearly as possible the same conditions.

RAPID METHODS FOR PHOSPHORUS.

FIG. 51.

RAPID METHODS.

Volumetric Method.*

This method gives an indirect determination of P by means
of the estimation of the MoO3 in the phospho-molybdate of
ammonium, in which form the P is precipitated. The MoO3 is
reduced to a lower state of oxidation by the reducing action
of Zn and H2SO4, and the reduced oxide is titrated with a
standardized permanganate solution, MoO3 being again formed
by the reaction.

Fig. 51 shows a
form of shaking-ma-
chine for shaking four
flasks at once. The
construction and
method of use are ap-
parent from the sketch.

Fig. 52 shows a
form of reductor which
is most convenient and
efficient The tube a
is 0.018 m. in inside
diameter and 0.300 m.
long. The small tube
below the contraction
with the stopcock c is
0.006 m. in inside di-
ameter and o.ioo m. long below the stopcock. The tube is filled
by placing at the point of contraction a flat spiral of platinum

* This method is the one prepared by the sub-committee on Methods of the Inter-
national Steel Standards Committee of the United States. It is by far the best method
known, and the results obtained by it are exceedingly accurate when the details are
carefully observed. The sub-committee consists of W. P. Barba, A. A. Blair, T. M.
Drown, C. B. Dudley (chairman), and P. W. Shimer.

ANAL YSIS OF IRON AND STEEL.

wire which nearly fills the tube and from the centre of which a
perpendicular wire extends downward a few millimetres into the
small tube. On top of this is placed a plug of glass wool, about
0.008 m. thick, and then asbestos, previously treated with con-
centrated hydrochloric acid, thoroughly washed, ignited, and dif-
fused in water, is poured into the reductor tube until it forms a
coating on top of the glass wool not over o.ooi m. thick. This

FIG. 52.

FIG. 53.

makes a filter which prevents very small pieces of zinc or other
materials from being carried through. It is necessary to clean
and refill the tube from time to time, as the filter after some use
becomes clogged and the liquid passes too slowly. The tube is
filled to within 0.050 m. of the top with granulated amalgamated
zinc, and a plug of glass wool is placed on top of the zinc which
prevents all spattering of the solution on the upper part of the

RAPID METHODS FOR PHOSPHORUS.

tube. The funnel b, which should be not less than o.ioo m. in
diameter across the top, is fitted tightly into the reductor tube by
means of a rubber stopper, as shown in the cut. The reductor
tube is fixed at such a height that when the block is removed
from under the flask /, the latter may be readily detached from
the tube and removed without disturbing the apparatus.

Fig. 53 shows the burette arranged for running the potassium
permanganate directly into the flask and needs no explanation.
It should be carefully calibrated.

The various beakers, flasks, graduates, etc., required by this
method need no special comment.

Reagents.

Nitric Acid. — Nitric acid of 1.135 SP- gr-> made by mixing
C. P. nitric acid 1.42 specific gravity with about three parts of
distilled water.

Strong Sulphuric Acid. — The C. P. material of 1.84 sp. gr.

Dilute Sulphuric Acid. — Sulphuric acid 2j^ per cent., by
volume, made by adding 25 c.c. of concentrated C. P. sulphuric
acid to i litre of distilled water.

Strong Ammonia. — The C. P. material of 0.90 sp. gr.

Dilute Ammonia. — 0.96 sp. gr., made by mixing concentrated
C. P. ammonia water of 0.90 sp. gr., with about one and a half
times its volume of distilled water.

Strong Solution of Potassium Permanganate, for oxidizing the
phosphorus and carbonaceous matter in the nitric acid solution of
a steel. Made by dissolving 12.5 to 15 grammes of crystallized
potassium permanganate in i litre of distilled water and filtering
through asbestos.

Standard Solution of Potassium Permanganate for titrating the
reduced solutions of ammonium phosphomolybdate. Made by
dissolving 2 grammes of crystallized potassium permanganate in
I litre of distilled water and filtering through asbestos. This
solution is standardized as follows: Weigh into 125 c.c. Erlen-

98 ANAL YSIS OF IRON AND STEEL,

meyer flasks, three portions of thoroughly cleaned soft steel wire,
in which the iron has been carefully determined, of from 0.15 to
0.25 grammes each, and pour into each of the flasks 30 c.c. of
distilled water and 10 c.c. of strong sulphuric acid. Cover with
a small watch-glass and heat until solution is complete. Add a
sufficient amount of the strong solution of potassium permanga-
nate to oxidize the iron and destroy the carbonaceous matter,
being careful to avoid an excess which would cause a precipitate
of binoxide of manganese. Should this occur, redissolve it by
adding a very few drops of sulphurous acid and boil off every
trace of the latter. Allow the solution in the flasks to cool and
add to each 10 c.c. of dilute ammonia. Pass through the
reductor and titrate in the flask.

In all cases the mode of procedure in using the reductor
should be as follows : Everything being clean and in good order
from previous treatment with dilute sulphuric acid, and washing
with distilled water, a little of the wash water being left in the
neck of the funnel b (Fig. 52), and the flask being attached to
the filter pump, pour 100 c.c. of warm dilute sulphuric acid into
the funnel and open the stopcock c. When only a little remains
in the neck of the funnel, transfer the solution to be reduced to
the funnel. This solution should be hot but not boiling. Pour
some of the dilute sulphuric acid into the vessel which contained
the solution to be reduced to wash it, and when only a little
solution is left in the neck of the funnel as before, add this to
the funnel in such a way as to wash it and follow with about 200
c.c. more of warm dilute sulphuric acid and finally with 50 c.c. of
hot distilled water. In no case allow the funnel b to get empty,
and close the stopcock c when there is still a little of the wash
water left in the funnel. This precaution prevents air from
passing into the reductor tube. A blank determination is made
by passing through the reductor a solution containing a mixture
of 10 c.c. strong sulphuric acid, 10 c.c. dilute ammonia, and 50
c.c. water ; preceded and followed by the dilute acid as described

RAPID METHODS FOR PHOSPHORUS.

above. The amount of potassium permanganate required to give
this blank a distinct color is subtracted from the amount required
to give the same color to each reduced solution.

To get the value of the permanganate solution, multiply the
weight of iron wire taken by the percentage of iron in the wire
and divide by the number of cubic centimetres of potassium per-
manganate used in the titration. This will give the value of I
c.c. of permanganate in terms of metallic iron. Multiply this
result by 0.88163, the ratio of molybdic acid to iron and the
product by 0.01794, the ratio of phosphorus to molybdic acid
and the result is the value of I c.c. of the permanganate solution
in terms of phosphorus. The ratio of molybdic acid to iron
given above is that found when a known amount of molybdic
acid in sulphuric acid solution is passed through the reductor in
the manner described above and then titrated with potassium
permanganate solution whose strength in terms of metallic iron
is known. The reduction of the molybdic acid in the reductor
in this case is to the form Mo24O37. The ratio of phosphorus
to molybdic acid given above is that found by the analysis of
the yellow precipitate of ammonium phosphomolybdate obtained
from nitric acid solution of iron under varying conditions.

Sulphurous Acid. — A strong solution of the gas in water.
Siphons of the liquefied gas may be obtained in the market.

Acid Ammonium Sulphite. — The strong C. P. solution of the
reagent diluted with 10 parts of water.

Ferrous Sulphate. — Crystals of the salt free from phosphorus.

These three reagents are for reducing the excess of binoxide
of manganese thrown down in oxidizing the carbonaceous matter
in the nitric acid solutions of the steels. Sulphurous acid is
preferred.

Molybdate Solution. — Weigh into a beaker 100 grammes of
pure molybdic anhydride, mix it thoroughly with 400 c.c. cold
distilled water and add 80 c.c. strong ammonia, 0.90 sp. gr.
When solution is complete, filter and pour the filtered solution

100

ANALYSIS OF IRON AND STEEL.

slowly with constant stirring into a mixture of 400 c.c. strong
nitric acid 1.42 sp. gr. and 600 c.c. distilled water. Add 50
milligrammes of microcosmic salt dissolved in a little water,
agitate thoroughly, allow the precipitate to settle for 24 hours,
and filter before using.

Acid Ammonium Sulphate Solution, for washing the precipitate
of ammonium phosphomolybdate. To I litre of water add 15 c.c.
of strong ammonia, 0.90 sp. gr. and 25 c.c. strong sulphuric acid,
1.84 sp. gr.

Amalgamated Zinc. — Dissolve 5 grammes of mercury in 25
c.c. strong nitric acid diluted with an equal bulk of water, dilute
to 250 c.c. and transfer to a stout flask of about 1000 c.c. capacity.
Pour into it 500 grammes of granulated zinc which will pass
through a 2O-mesh sieve, but not through a 3O-mesh. Shake it
thoroughly for a minute or two and then pour off the solution,
wash the zinc thoroughly with distilled water, dry, and preserve
in a glass bottle for use.

Operation.

Weigh 2 grammes, or in case of steels containing over 0.15
per cent, phosphorus, I gramme of the steel into a 250 c.c.
Erlenmeyer flask, pour into it 100 c.c. of nitric acid 1.135 sp.
gr., and cover with a small watch-glass. Heat until the solution
is complete and nitric oxide is boiled off. Add 10 c.c. of the
strong potassium permanganate solution, boil until the pink color
has disappeared and binoxide of manganese separates. Continue
the boiling for several minutes, then remove from the source of
heat and add a few drops of sulphurous acid, ammonium sulphite,
or a small crystal of ferrous sulphate, repeating the addition at
intervals of a minute until the precipitated binoxide of manganese
is dissolved. Boil two minutes longer, place the flask in a vessel
of cold water, or allow it to stand in the air until it feels cool to
the hand, and then pour in 40 c.c. of dilute ammonia 0.96 sp. gr.
The precipitated ferric hydrate will redissolve when the liquid is

RAPID METHODS FOR PHOSPHORUS. IOI

thoroughly mixed. When the solution is about the temperature
of the hand, say 35° C., add 40 c.c. of molybdate solution at the
ordinary temperature, close the flask with a rubber stopper, and
shake it for five minutes, either by hand or in the machine, Figure
5 1 . Allow the precipitate to settle for a few minutes, filter on a
0.090 m. filter, and wash with acid ammonium sulphate solution
until 2 or 3 c.c. of the wash water give no reaction for molyb-
denum with a drop of ammonium sulphide. Pour 5 c.c. of
ammonia 0.90 sp. gr. and 20 c.c. of water into the flask to dis-
solve any adhering ammonium phosphomolybdate and then pour
it on the precipitate in the filter, allowing the filtrate to run into
a 250 c.c. Griffin's beaker. Wash out the flask and wash the
filter with water until the solution measures about 60 c.c. Add
to the liquid in the beaker 10 c.c. strong sulphuric acid and pass
it through the reductor exactly in the manner described for the
solutions of ferric sulphate in standardizing the solution of potas-
sium permanganate. By adding the strong sulphuric acid to the
ammoniacal solution immediately before passing it through the
reductor it is heated sufficiently by the chemical action to insure
thorough reduction. In washing be careful that no air passes
into the reductor, and when the water has been drawn through,
leaving a little still remaining in the stem of the funnel, close the
stopcock, detach the flask F, wash off the drawn out portion
of the reductor tube into it, and titrate the solution with the
standard permanganate. The reductor should be so arranged
that the whole reduction occupies about 3 or 4 minutes. The
solution that passes through should be bright green in color.
In adding the permanganate, the green color disappears first,
and the solution becomes brown, then pinkish yellow, and ulti-
mately colorless. Continue the addition of the permanganate
drop by drop, shaking the flask vigorously until the solution
assumes a faint pink coloration, which remains after standing
one minute. Subtract from the reading of the burette the
amount given by a blank determination, obtained exactly as

IO2 ANAL YSIS OF IRON AND STEEL.

described under the method given above for standardizing the
permanganate solution, multiply the number of c.c. so obtained
by the value of I c.c. in terms of phosphorus, multiply by 100
and divide by weight taken, and the result is the percentage of
phosphorus in the steel.

When a large number of analyses are to be carried along at
once the following modification is recommended : Obtain the
yellow precipitate and dissolve in ammonia exactly as described
above, except that the solution is allowed to run into the flask
in which the precipitation was made, and the washing of the
filter is continued until the solution amounts to 75 c.c. Add
now to the flask 5 grammes of pulverized zinc, 100 mesh,
pouring it into the flask through a funnel to prevent any zinc
clinging to the sides of the flask. Then add to the flask 1 5 c.c.
strong sulphuric acid 1.84 sp. gr. This is most conveniently
done in practice by letting it run in from a glass-stoppered
burette. Close the flask at orfce with a rubber stopper carrying
a glass tube bent twice at right angles, the further arm dipping
into a beaker containing a saturated solution of sodium bicar-
bonate. The flask should now stand undisturbed for about
thirty minutes, when, if all action has ceased, it is ready to
titrate with permanganate. The solution should be green, not
brown. The temperature of the solution at the end of thirty
minutes is about 40° C. and the titration succeeds best if done
at this temperature. But the flask may stand a couple of hours
without reoxidation of the reduced molybdic acid, and may
then be successfully titrated. If the solution changes in color
to brown the determination should be rejected, as the result will
be too low. A blank should be made by adding to another flask
65 c.c. of water, 10 c.c. of dilute ammonia 0.96 sp. gr., 5 grammes
of the lOO-mesh zinc, added in the manner described, and 15 c.c.
of strong sulphuric acid 1.84 sp. gr. This flask should be treated
the same as the others and the amount of permanganate it uses
up should be deducted from the amount required by each flask

RAPID METHODS FOR PHOSPHORUS.

containing a test. When this method is used the reduction is
practically complete to Mo2O, so that the factor 0.85714 must be
used instead of 0.88163.

Example.

0.1745 grammes of wire requires 50.0 c.c. of permanganate to
give the required color. A blank determination gave o.i c.c., so
that the wire actually required 49.9 c.c. permanganate. The wire
contained 99.87 per cent, of iron, then 0.1745 X 0.9987 -=- 49.9
equals 0.0034923, or i c.c. of permanganate equals 0.0034923
grammes metallic iron. Then multiplying the value in iron
by the ratio of molybdic acid to iron 0.88163 or 0.85714 and the
product by the ratio of phosphorus to molybdic acid 0.01794,
we have 0.0034923 X 0.88163 X 0.01794 equals 0.000055238, or
i c.c. permanganate equals 0.000055238 grammes of phosphorus.
Again the precipitated ammonium phosphomolybdate from 2
grammes of steel required 35.6 c.c. permanganate less blank
o.i c.c. equals 35.5 c.c.; 35.5 X-O.OOOO55238 X 100 -H 2 equals
0.098 per cent, phosphorus.

Notes and Precautions.

It will be observed that the method given above oxidizes the
phosphorus in the iron by means of nitric acid, completes and
perfects this oxidation and possibly neutralizes the effect of the
carbon present by means of potassium permanganate, and then
separates the phosphoric acid from the iron by means of mo-
lybdic acid. The molybdic acid in the yellow phosphomolybdate
is subsequently determined by means of potassium permanganate,
the phosphorus being determined from its relation to the molyb-
dic acid in this precipitate. The method given above applies to
steel and wrought iron, but it is not yet recommended for pig-
iron.

It is hardly necessary to say that all the chemicals and
materials used in the analysis are assumed to be free from im-
purities that will injuriously affect the result.

IO4

ANAL YSIS OF IRON AND STEEL.

1.135 SP- gr- nitric acid apparently oxidizes the phosphorus
just as successfully as a stronger one, while by its use solution
is sufficiently rapid, and there is less trouble during the subse-
quent filtration due to silica.

The boiling of the solution to remove nitrous acid and assist
the action of the oxidizing permanganate seems to be essential.
Some steels may not require 10 c.c. of the permanganate and
some, like washed metal high in carbon, may require even more.
It is essential that enough should be added to cause a precipita-
tion of binoxide of manganese and to give a strong pink color
to the solution. This color gradually disappears on boiling.
Less is required if the permanganate is added in small successive
portions. Boiling two minutes after reducing the binoxide of
manganese removes any nitrous acid that may be formed by that
operation.

In washing the yellow precipitate it shows some disposition to
crawl up to the top of the filter. Care should be taken therefore
to have the filter fit the funnel so closely that even if the precipi-
tate does crawl over the top it will not be lost while washing the
filter completely to the top. It is very easy to leave enough
molybdic acid in the top of the filter, even though the washings
are tested, to cause an error of .005 per cent, in the determina-
tion.

It is best to make up molybdate solution rather frequently.
It is also best to keep it in the dark at a temperature not above
28° to 30° C. Much of the so-called molybdic acid of the market
is molybdate of ammonium or molybdate of some other alkali.
This fact cannot be ignored in making up the molybdate solution.
A series of experiments with various molybdic acids and alkaline
molybdates obtained in the market, indicates that if the amount
of molybdic acid in the solution is that called for by the formula,
irrespective of whether this amount is furnished by pure molybdic
acid or by any of the commercial molybdates referred to, the re-
sult will be much nearer the truth than if this is not done. Good

RAPID METHODS FOR PHOSPHORUS. IOjj

molybdic acid is the best, but the alkaline molybdates can be
used. The amount of molybdic acid in these molybdates can
readily be determined by dissolving o.iooo gramme in 60 c.c.
of water to which 10 c.c. of dilute ammonia has been added,
filtering, adding 10 c.c. strong C. P. sulphuric acid, and passing
through the reductor as above described. The method given
in the example above enables the amount of molybdic acid to
be determined. If the molybdic acid as obtained in the market,
or the ammonia used in dissolving it, contains any soluble sili-
cates, the resulting molybdate solution will be yellowish in color
and the determinations made with this solution will be high,
owing apparently to ammonium silicomolybdate being dragged
down with the phosphomolybdate. Treatment of the molybdate
solution with microcosmic salt, as described, overcomes this diffi-
culty and gives a perfectly colorless molybdate solution. A
molybdate solution tinged with yellow should never be used.
It will be observed that the molybdate solution recommended
above contains much less nitrate of ammonia than is given by
many of the formulas now in use. Experience shows that a
molybdate solution made on this formula keeps much better
than those containing more ammonium nitrate. It will also be
observed that the amount used for each determination is less
than many methods employ. It is believed that the amount
recommended is sufficient and that the ammonium nitrate re-
quired to assist the formation of the yellow precipitate is fur-
nished by the 40 c.c. of dilute ammonia added to the nitric acid
solution of the steel. Of course the molybdate solution recom-
mended above cannot be used for other work interchangeably
with that made on the older formulas, on account of lack of
ammonium nitrate.

The directions in regard to the reductor, both as to making
and use, should be strictly followed. By the use of the stop-
cock, and the amalgamated zinc, and by keeping a little liquid
in the neck of the funnel, the same blank can be obtained from

IO6 ANALYSIS OF IRON AND STEEL.

a reductor almost continuously, even though two or three days
of standing intervene between blanks. It is, however, always
advisable to treat with dilute sulphuric acid and wash before
using, even though only one night has elapsed since the last
previous use. If the solution to be reduced does not contain
enough acid or is not warm enough, the reduction will not be
complete. Care should therefore be taken not to allow too much
mixing of the dilute sulphuric acid with the solution to be re-
duced, either in the funnel or in the reductor tube itself, The
best asbestos to use is the mineral known as actinolite, but any
fibrous mineral which will act as a filter and not be dissolved by
the acids used may be employed. Glass wool alone will not do,
as a good filter is essential in order that neither small particles
of zinc nor impurities in the zinc may be drawn down into the
flask with the reduced solution. The consumption of zinc is
very small.

In testing with ammonium sulphide, to see whether the wash-
ing of the yellow precipitate is complete, good results are ob-
tained by putting two or three drops of yellow ammonium
sulphide into a few cubic centimetres of distilled water, and
allowing the washings to drop into this solution from the stem
of the funnel. If iron is present in the washings it will show
while the solution is still alkaline. By allowing the washings
to continue running into the ammonium sulphide solution it
soon becomes acid, when molybdenum, if any is present, shows
by a more or less brownish color. If the acid solution is pure
white from separated sulphur the washing is complete.

Since the acidity of the solution in which the yellow precipi-
tate is formed has an influence on its composition, it is quite
desirable that the sp. gr. of the 1.135 nitric acid and of the
0.96 ammonia should be taken with some care. The tempera-
ture at which the figures are correct is 15° C. It is best to use
the Westphal balance in determining these gravities, but failing
this, a sufficiently delicate hydrometer can be employed.

RAPID METHODS FOR PHOSPHORUS,

In using the reduction with 5 grammes of loo-mesh zinc, it
will be observed that as the zinc becomes nearly all dissolved
a blackish residue remains. This residue seems to be metallic
lead. It disappears slowly during the titration and apparently
uses up some permanganate. It takes a little longer to secure
a satisfactory end reaction with the loo-mesh zinc, as the pink
color fades out several times before it will remain permanent
for one minute. It is essential that air should be excluded
from the flask after the reduction is nearly complete, and it
is for this purpose that the sodium bicarbonate solution is
used. A tendency to suck the soda solution back into the
reducing flask will be noticed, due to the cooling of the
flask. The reduction should be made in a place free from
draughts.

With the amalgamated zinc in the reductor made as above
described the blank generally uses up about O.I c.c. of the
standard permanganate solution. The blank when using the
reduction by means of 5 grammes loo-mesh zinc usually amounts
to 0.6 c.c. of the standard permanganate, and may be higher.
Pulverized zinc is rarely free from sulphides, and while this seems
not to be a very important matter, it is nevertheless not recom-
mended to use, either in the reductor or in the flask reduction, a
zinc that gives a high blank.

If the amount of sulphurous acid or other reagent added to
the nitric acid solution to remove the precipitated binoxide of
manganese is insufficient, a brown stain will be left on the filter
paper after the yellow precipitate is dissolved in ammonia. This
may occur even though the nitric acid solution looks clear, and
as no harm can arise from a slight excess of the reducing agent,
it is usually more satisfactory to add an excess. It is not de-
sirable to add the reducing agent to the solution while boiling,
as under such circumstances it frequently boils over.

It is rather essential to use the dilute sulphuric acid warm, so
that the general temperature of the reductor may be kept up.

IO8 ANALYSIS OF IRON AND STEEL.

A good method for cleaning the wire in standardizing the
potassium permanganates is as follows : Take a round lead pencil
and make a hole in it with a pin near the end. Insert the end of
the wire in this hole and revolve the pencil until there are two
turns of the wire around it. Hold the turns firmly in one hand
and cut the wire so that about 0.75 m. will remain attached to
the pencil. Draw this wire through a piece of folded fine sand-
paper several times and then several times through a piece of
filter paper. Seize the wire near the pencil with the filter paper
and cut off the part which was wound around the pencil and
remove it. Then insert the end of the cleaned wire in the hole
and revolve the pencil with one hand, holding the wire in the
filter paper in the other hand, until it is all wound loosely on
the pencil. Push the coiled wire off the end of the pencil. It
is now in a convenient form for weighing.

Direct Weighing of the Phospho-Molybdate.

Instead of using the volumetric method, some chemists pre-
fer to weigh the yellow precipitate. Mr. Wood's method* is
as follows :
Wood's Dissolve 1.63 grammes steel in a six-ounce Erlenmeyer flask

method.

in 30 c.c. warm nitric acid, 1.2 sp.gr., place the flask over a
Bunsen flame and evaporate down to 10 or 15 c.c., hastening the
evaporation by blowing a gentle current of air into the flask.

Heat 50 c.c. of molybdate solution to 5O°-55° C, add it to
the solution in the flask, and shake well. Complete precipita-
tion should take place in from three to five minutes. Filter on
the pump in a 7 c.m. Munktell's No. I filter which has been pre-
viously washed, dried at 100° C., and weighed. Wash with dilute
nitric acid, suck dry, wash once with alcohol and thoroughly
with ether, and place the filter containing the precipitate in a
funnel in an air-bath heated to 110° C. The funnel in the bath

* Communicated to the author. Mr. Wood states that the details adapting this
to a " rapid method" were worked out by Mr. J. A. Nichols, of the Homestead Works.

DETERMINATION OF MANGANESE.

is connected with the exhaust so that the precipitate and filter
are thoroughly dried in from one to three minutes, according to
the size of the precipitate. Weigh, and I milligramme of precipi-
tate will be equal to .001 per cent, of phosphorus in the steel.

In the case of pig-iron and spiegel, the metal after solution
in nitric acid, 1.2 sp. gr., is diluted with 20 c.c. water, 5 drops
of hydrofluoric acid are then added, the solution is boiled for
two or three minutes, filtered through asbestos on the pump, and
concentrated to 15 c.c.

15 c.c. of chromic acid is added, the solution is boiled down
again and precipitated as above. The hydrofluoric acid prevents
the separation of gelatinous silica, but does not interfere with
the precipitation of the phosphorus.

This method will not work with ferro-manganese, as the
combined carbon is not completely oxidized to prevent the pre-
cipitation of all the phosphorus.

The solutions referred to above are prepared as follows:

Molybdic acid solution: To 1200 c.c. water add 700 c.c. Reagents
ammonia, sp. gr. 0.88, and I pound molybdic acid ; when the
molybdic acid is dissolved add 300 c.c. nitric acid, sp. gr. 1.42,
and cool. Pour this solution into a mixture of 4800 c.c. water
and 2000 c.c. concentrated nitric acid. Filter for use after
standing twenty-four hours.

Chromic acid solution: 1.42 sp.gr. nitric acid saturated with
chromic acid.

DETERMINATION OF MANGANESE.

The Acetate Method.

Dissolve I gramme of drillings in 15 c.c. HNO3, 1.2 sp.gr.,
in a No. 2 Griffin's beaker. Evaporate to dryness in the air-
bath, and heat to decompose carbonaceous matter. Allow the
beaker to cool, add 10 c.c. HC1, heat carefully until all the

IIO

ANALYSIS OF IRON AND STEEL.

For steel and
iron ultra-

Na2co3.

importance

of avoid-

ing excess

Fe2O3 is dissolved, evaporate to dryness to get rid of all the
HNO3, redissolve in 10 c.c. HC1, and evaporate carefully until
the solution is almost syrupy. Dilute with cold water to about
IOO c.c., and filter off the insoluble matter, allowing the filtrate
and washings to run into a No. 6 Griffin's beaker. In the case
°f steel or puddled iron the filtration may be omitted, the solu-
^on being poured into the large beaker, and the rinsings of
the small beaker added. To the solution in the large beaker,
which should amount to about 200 c.c., add a solution of car-
bonate of sodium very slowly, stirring vigorously. The solution
will finally become very dark red in color, and the precipitate
formed will redissolve very slowly. Add the solution of car-
bonate of sodium 2 or 3 drops at a time, stir well, and allow the
solution to stand several minutes, to see whether the precipitate
will redissolve or not. When, under these circumstances, a
decided precipitate remains, add 2 drops of HC1, stir well, and
allow the solution to stand for some minutes ; if the solution
does not clear, add 2 drops more, and stir again. If the first
part of the operation has been carefully conducted, this amount
of HC1 will usually be sufficient, but if, for any reason, too
large a precipitate has been formed, it may require a few drops
more. It is important, however, that no more HC1 be added
than just enough to redissolve the precipitate formed by the
carbonate of sodium, and, to insure this, the solution should
be well stirred and allowed to stand a sufficient length of time
after each addition of HC1. The solution may be so dark in
color that it is difficult to see when the precipitate does finally
disappear, but by standing the beaker on a piece of white
paper the light reflected through the bottom of the beaker will
greatly diminish the difficulty. When, under this method of
procedure, the solution clears, add 2 grammes of acetate of
sodium dissolved in a few c.c. of water, stir well, and dilute
the solution to about 700 c.c. with boiling water. Heat it to
boiling, and allow it to boil for about ten minutes, then remove

DETERMINATION OF MANGANESE. IU

it from the tripod, and allow the precipitated hydrate and basic
acetate of iron to settle. Decant the clear, supernatant fluid on Filtering off
a large washed German filter, throw the precipitate on, and
wash it two or three times with boiling water, allowing the
filtrate to run into a large beaker or flask, from which it can
be transferred to a platinum or porcelain dish and evaporated
rapidly. When the precipitate has drained quite dry, by means
of a platinum spatula transfer it . to the beaker in which the
precipitation was first made ; dissolve the precipitate which
remains adhering to the filter, and that which remains on the
blade of the spatula, by pouring around the edge of the filter
and on the spatula held over it 10 c.c. HC1 diluted with twice
its volume of hot water, allowing it to run into the beaker
containing the precipitate. Wash the filter free from chloride
of iron with cold water, and heat the beaker containing the
precipitate until the latter is dissolved. Cool the solution, and
repeat the precipitation, filtration, and resolution of the pre-
cipitate precisely as in the first case, adding this filtrate to the
first one. Precipitate, filter, and wash a third time in the same Evaporation
manner, evaporate all the filtrates down together until they are
reduced to about 300 c.c. in volume, and transfer this solution
to a No. 3 beaker.

If during the evaporation any manganese has become oxi-
dized by exposure to the air, it forms a hard ring on the side
of the capsule, and may be dissolved, after the solution is poured
into the beaker, by two or three drops of HC1, and washed into
the beaker. Should any oxide of iron separate out, pour the
solution in the capsule through a small filter, allowing it to run
into the beaker, wash the precipitate with hot water, dissolve
it in a very few drops of dilute HC1, and let it run into a No. I
beaker. Add just enough solution of carbonate of sodium to
precipitate it, make it faintly acid with acetic acid, boil it, and
filter into the main solution.

This solution now contains all the manganese, nickel, and

112

ANALYSIS OF IRON AND STEEL.

Separation
of Cu, Ni,
and Co
from the
Mn.

Precipita-
tion of
MnO2 by
Br.

Precipita-
tion of Mn2
(NH4)2
P2O8+Aq.

cobalt and the greater part of the copper which may have been
in the metal. Add to it 10 grammes of acetate of sodium and
a few drops of acetic acid, heat it to boiling, and pass a current
of H2S through the boiling solution for fifteen minutes. This
will precipitate the copper, cobalt, and nickel. Filter off the
black sulphides, boil the filtrate to expel the excess of H2S, let
the solution cool somewhat, and add bromine-water in excess.
If no precipitate forms at first, stand the solution, which should
be colored by the bromine-water, in a warm place for an hour
or two, to allow the precipitate of MnO2 to separate out. If a
precipitate forms immediately, add bromine-water until, when
the precipitate settles, the solution is strongly colored by it, and
stand it aside for an hour or two. At the end of this time, the
precipitate having settled and the supernatant fluid being still
colored by the bromine, heat it carefully, finally to boiling, and
expel the excess of bromine; allow the precipitate to settle,
filter, wash very carefully, and avoid stirring up the precipitate
when it is on the filter, as it has a tendency to go through.
Dissolve the precipitate on the filter in sulphurous acid water
containing a little HC1; allow the solution to run into a platinum
dish, and wash the filter well. A little of the SO2 water will
quickly dissolve any MnO2 which may adhere to the beaker in
which it was precipitated, and this may be poured on the filter.
Boil the solution in the dish to expel the excess of SO2, add
5 to 20 c.c. of a clear filtered solution of microcosmic salt, heat
to boiling, and add, with constant stirring, NH4HO drop by
drop. When the precipitate of phosphate of ammonium and
manganese begins to form, stop adding NH4HO, and stir until
the precipitate becomes crystalline. When this change occurs,
add one more drop of NH4HO ; the additional precipitate formed
will be curdy, but a few seconds' continued stirring at the boiling
temperature will change it to the silky crystalline condition.
Continue the addition of NH4HO in exactly this manner until
the precipitate is all down and further additions of NH4HO fail

DETERMINATION OF MANGANESE. n^

to change the silky appearance. Add a dozen drops of NH4HO
in excess, remove the dish from the light, and stand it in ice-
water until perfectly cold. Filter on an ashless filter, wash with Solution of

r . f /•,- NH4NO3

cold water containing 10 grammes of nitrate of ammonium (dis- for wash-
solved in water made faintly alkaline with NH4HO and filtered) Jj^.
in 100 c.c. until the filtrate gives no reaction for HC1, dry, tate-
ignite, and weigh as Mn2P2O7, which contains 38.74 per cent. Mn.
During the precipitation of the phosphate of ammonium and
manganese the stirring must not be discontinued for an instant,
as the solution has a great tendency to bump when the precipitate
is allowed to settle. The crystalline condition of the precipitate,
which is absolutely necessary for the success of the determina-
tion, can be most readily brought about by the means described
above. It can, of course, be accomplished by adding an excess
of NH4HO at once, but it will require much more boiling and
stirring than the method above described. The final precipita-
tion as phosphate of ammonium and manganese, due to Dr.
Gibbs, is much the most accurate method known. A common
practice, however, is to wash the bromine precipitate of hydrated weighing as
binoxide of manganese, dry, ignite, and weigh as Mn3O4, which
contains 72.05 per cent. Mn. There are two objections to this objections

to this.

method of procedure : first, the difficulty of washing the MnO2
free from sodium salts ; secondly, the uncertainty as to the exact
state of oxidation of the ignited oxide of manganese. The first
of these objections Eggertz claims to overcome by washing the
precipitated MnO2 with water containing I per cent, of HC1.
It may also be overcome, or rather the danger may be avoided,
by using no fixed alkalies. By this method, nearly neutralize
the HC1 solution of the iron or steel by NH4HO, then add a
solution of carbonate of ammonium exactly as directed above
for carbonate of sodium, and finally, instead of acetate of sodium, Avoidmgus*
add acetate of ammonium (5 c.c. of NH4HO slightly acidulated alkalies,
by acetic acid). Evaporate the filtrates obtained in this way to
about 500 c.c., transfer to a flask of about I litre capacity, and

114

ANAL YSIS OF IRON AND STEEL.

Variable
composi-
tion of
ignited
oxide of
manga-
nese.

Weighing
as MnS.

Source of
error in
acetate
method.

Amount of
NaC2H302
necessary.

cool. When perfectly cold, add 3 or 4 c.c. bromine, shake well,
and when the solution is strongly colored all through by bro-
mine, add an excess of NH4HO, and heat to boiling. Filter,
wash with hot water, dry, ignite, and weigh as Mn3O4.

The second objection seems, according to Pickering,* to be
well founded, the amount of manganese in the ignited oxides
varying from 69.688 per cent, to 74.997 per cent., according to
the temperature to which they were heated and other undeter-
mined conditions. This cause of error may be avoided by
weighing the precipitate as MnS, containing 63.18 per cent. Mn.
This method, due to H. Rose,f is carried out as follows : Ignite
the oxide in a porcelain crucible, allow it to cool, mix it with
5 or 6 times its volume of flowers of sulphur, place the crucible
on a triangle, and insert the bowl of a clay tobacco-pipe, which
should be large enough to quite fill the top of the crucible and
too large to reach to the precipitate. Pass through the stem
a current of dry hydrogen until all air is expelled, heat the
crucible gradually to as high a heat as a good Bunsen burner
will produce, cool in the current of hydrogen, and weigh as
MnS.

General Remarks on the Acetate Method.

The chief source of error in the acetate method, as it is
usually practised, is in the addition of too much acetate of
sodium, whereby the manganous chloride is changed to manga-
nous acetate, which, according to Kessler,J is readily decomposed
to manganous oxide and acetic acid. Under these circumstances,
a larger amount of manganese is precipitated with the iron than
would be the case if a less amount of acetate of sodium were
added. When acetate of sodium is added to ferric chloride, the
reaction may be written, 6NaC2H3O2,3H2O + Fe2Q6==6NaCl-f-
Fe2(C2H3O2)6+3H2O; and to precipitate the iron as ferric acetate

* Chem. News, xliii. 226.
\ Chem. News, xxvii. 14.

f Rose, Quant. Anal. (French ed.), p. 104.

DETERMINATION OF MANGANESE. n-

in i gramme of metal would necessitate the use of 8 grammes
of acetate of sodium. But, as Kessler in the same article
remarks, when a solution of ferric chloride is treated with car-
bonate of sodium and HC1 exactly as described above, a liquid
is formed which contains 14 times its equivalent of ferric hydrate
in solution. Consequently ^ gramme of acetate of sodium would
be sufficient to precipitate I gramme of iron as ferric hydrate
and basic acetate. In order, however, to precipitate the manga-
nese as MnO2 by bromine, it is necessary to convert all the man-
ganous chloride into manganous acetate : consequently an excess
of acetate of sodium is added before adding bromine. If, when
making the acetate precipitation, the solution contains any ferrous
chloride, a "brick-dust" precipitate is usually formed, which Brick-dust
generally passes through the filter, and is very difficult to dis- tate.
solve or manage in any way. It is usually the shortest and best
plan, in this event, to start a fresh portion and throw away the
other.

The Nitric Acid and Chlorate of Potassium Method.
(Ford's Method^

The acetate method is at best very tedious, and when the
amount of manganese is very small it is of course desirable to
work on larger amounts than I gramme of the sample, but the
iron precipitate in this event is so large that it becomes very
difficult to manage it properly. With Ford's method, however,
there is almost no limit to the amount which can be operated
upon, and many experiments have shown that with proper pre-
cautions it is an extremely accurate process. The reaction on
which the process is based was first noticed by Hannay* in 1878;
but Fordt first worked out the method in its present practical

Method for

form. Dissolve 5 grammes of borings in a No. 3 beaker in steel and

puddled

60 c.c. HNO3, 1.2 sp. gr., evaporate down until the solution is iron.

* Jour. Chem. Soc., xxxiii. 269. f Trans. Inst. Min. Engineers, ix. 397.

ANALYSIS OF IRON AND STEEL.

Filtering the
cold solu-
tion.

Effect of
N2O3 in
HN03.

Separation
from small
amounts of
Fe203 by
NH4HO.

almost syrupy, then add 100 c.c. strong HNO3, 1.4 sp. gr., and
5 grammes KC1O3. Stand the beaker on a tripod with a thin
piece of sheet asbestos, about I inch (25 mm.) in diameter, in
the centre of the wire gauge or on the air-bath, and heat the
solution to boiling. Boil the solution fifteen minutes, remove
the light, add 50 c.c. strong HNO3 and 5 grammes KC1O3,
replace the light, and boil fifteen minutes longer, or until the
yellowish fumes from the decomposition of the KC1O3 are no
longer given off. Cool the solution as rapidly as possible by
standing the beaker in cold water, filter on the pump, using the
cone* or glass filtering-tube with asbestos filter, f and wash two
or three times with strong HNO3, which must be free from
nitrous fumes.J Nitrous acid reduces MnO2 to MnO, which then
dissolves in HNO3. Its presence may be recognized by the
yellow color it imparts to HNO3, and it may be removed by
blowing air through the acid. It is always formed in HNO3
which has been exposed to sunlight, and for that reason this
acid should be kept in a dark place. Suck the precipitate dry,
and transfer it, with the asbestos filter, to the beaker in which
the precipitation was made. Pour into the beaker 10 to 40 c.c.
strong sulphurous acid water, which will dissolve the precipitate
almost instantly. By pouring it through the cone or filtering-
tube, any adhering precipitate will be dissolved and carried into
the beaker. As soon as the precipitate is dissolved, add 2 to 5
c.c. HC1, and filter from the asbestos into a No. I beaker, wash-
ing with hot water. Heat the filtrate until the excess of SO2
is driven off, add bromine-water until the solution is strongly
colored with it, and boil off the excess of bromine. Add NH4HO
until the solution smells quite strongly of it, boil for a few
minutes, and filter into a No. 3 beaker. Wash several times with

* See page 26. f As described under Methods for Determination of Carbon.

J It is always well to transfer the filtrate and washings to a No. 4 beaker, add 2
grammes KC1O3, and boil again, to see whether any further precipitate of MnO2 is
formed.

DETERMINATION OF MANGANESE.

hot water, remove the beaker, dissolve the ferric hydrate on
the filter in dilute hot HC1 (l part of acid to 3 of water),
allowing the solution to run back into the beaker in which the
precipitation was made, and wash the filter with hot water. Boil
this filtrate for a few minutes to drive off the chlorine which
may be present from the solution of any little MnO2 precipitated
with the ferric hydrate, reprecipitate by NH4HO as before, filter,
and repeat the solution, precipitation, and filtration, allowing all
the filtrates from the ferric hydrate to run into the No. 3 beaker.
Acidulate this solution, which will be about 300 or 400 c.c. in
volume, with acetic acid, heat to boiling, and pass H2S through
the boiling solution for ten or fifteen minutes. Filter into a Separation
platinum dish from any sulphide of cobalt, which is the only baU.
metal likely to be present with the manganese ; boil off the H2S
after adding a little HC1, add microcosmic salt, and precipitate,
filter, ignite, and weigh, as directed on pages 112 and 113, as
Mn2P2O7.

Steels containing much Silicon.

In steel high in silicon, 0.2 per cent, and over, the gelatinous
silica formed is very apt to clog the filter when operating as
described above, and it is better to dissolve the sample in HC1,
evaporate to dryness, being careful not to heat it too hot, redis-
solve carefully in 50 c.c. strong HNO3, boil down until nearly
syrupy to destroy all the HC1, redissolve in 100 c.c. strong
HNO3, and precipitate as directed above.

Instead of dissolving in HC1, Mr. Wood suggests adding a
few drops of hydrofluoric acid to the nitric acid solution before
evaporating. This seems to work extremely well, and saves
much time in the case of high silicon steels. It may also be Si°»-
used to advantage in the case of pig-iron instead of the method
given below.

Pig-iron.

Dissolve 5 grammes in 50 c.c. dilute HC1 (i part HC1 to I
part water), filter on a washed German filter into a No. 3 beaker,

US ANALYSIS OF IRON AND STEEL.

evaporate to dryness, redissolve in 50 c.c. strong HNO3, and
proceed as in the case of " steel high in silicon."

Spiegel and Ferro-manganese.

It is best to use only I gramme of spiegel or ferro-manganese

of 20 to 40 per cent, manganese and .5 gramme of very high, 60

Variation in to 8o per cent, ferro-manganese. In the latter, indeed, it is better

methodfor to use the acetate method with NH4HO and NH4C2H3O2, and,

ga^esT*"" omitting the precipitation by bromine, boil off the H2S from

the nitrate from the insoluble sulphides, after adding HC1, and

then precipitate by microcosmic salt as directed above.

RAPID METHODS.
Volumetric Methods.

Volhard's Method*

This method is based on the principle announced by Moraw-
ski and Stingl,f that when permanganate of potassium is added
to a neutral manganous salt all the manganese is precipitated,
in accordance with the reaction 4KMnO4 -j- 6MnSO4 + 4H2O =
ioMnO2 + 4KHSO4+2H2SO4. When all the manganous salt
is oxidized, the solution is colored by the permanganate, which
thus indicates the end reaction. The permanganate used for
titrating iron ores may be used for this determination, and, its
value being determined, as directed, in terms of Fe, the cal-
Caicuiation culation for Mn is as follows : The reaction, when perman-
ofperman- ganate is added to a solution of ferrous sulphate, is ioFeSO4-|-
ganate" 0 8H0 or 2

molecules of permanganate oxidize 10 molecules of FeSO4. Now,
as 2 molecules of permanganate oxidize 3 molecules of man-
ganous sulphate, while 2 molecules of permanganate oxidize 10
molecules of ferrous sulphate, the oxidizing power of the per-

* Liebig's Annalen, Band cxcviii. p. 318; Chem. News, xl. 207.
•j- Chem. News, xxxviii. 297.

RAPID METHODS FOR MANGANESE. U

manganate is only three-tenths as great in the former case as it is
in the latter, and its value in Mn is to its value in Fe as 3 is to
10, or |-| X YQ = iro"- Therefore the value of the permanganate Details
in Fe multiplied by £|-| or 0.2946== its value in Mn. Dissolve method.
1.5 grammes of borings in a platinum or porcelain dish in 25
c.c. HNO3, 1.2 sp. gr. When solution is complete, add 12 c.c.
dilute H2SO4 (i part concentrated H2SO4 and I part water), and
evaporate to dryness, as directed on page 20, heating until
fumes of H2SO4 are given off in order to destroy all the car-
bonaceous matter. Or dissolve in HNO3 as above, evaporate
to dryness, and heat on the tripod until the carbonaceous
matter is destroyed; dissolve in 15 c.c. HC1, add 12 c.c. dilute
H2SO4 as above, and evaporate until fumes of H2SO4 are given
off. Allow the dish to cool, add 100 c.c. water, and heat until
all the ferric sulphate is dissolved. Wash into a carefully
graduated 300 c.c. flask, so that with the washings the solution
may not exceed 200 c.c. in volume, and add solution of car-
bonate of sodium until the precipitate which is first formed
dissolves only with difficulty. Then add slowly zinc oxide*
suspended in water, shaking well after each addition until the
iron is precipitated, which will be shown by the sudden coagu-
lation of the solution. The precipitate will then settle, leaving
a slightly milky supernatant liquid. Fill the flask exactly to
the mark on the neck (300 c.c.), and mix thoroughly by pour-
ing the entire contents of the flask into a large, clean, dry
beaker, and back again into the flask, repeating this several
times. Allow the precipitate to settle for a few minutes, and
pour the solution through a large, dry filter. Fill a 200 c.c.
pipette with this filtrate, which will, of course, represent exactly
I gramme of the sample, run it into a flask of about 500 c.c.
capacity, heat to boiling, and add 2 drops of HNO3, sp. gr. 1.2.
Now add permanganate solution slowly from a burette, shaking

* See page 58.

12Q ANALYSIS OF IRON AND STEEL.

after each addition to mix the solution and facilitate the collec-
tion of the precipitated hydrated peroxide of manganese. When
the reaction is nearly finished, the solution will be slightly col-
ored by the permanganate, but the color disappears after shaking
the flask and allowing it to stand for a moment. Finally, how-
ever, a drop or two will give the solution a permanent pink color,
which will not disappear for several minutes. The number of c.c.
of the permanganate solution used multiplied by the factor found
(the Fe factor of the permanganate multiplied by .2946) is the
amount of manganese in the sample. If, during the addition
of the permanganate, the solution should become cool and the
precipitate fail to collect and settle quickly, heat the solution,
Applicable but not quite to the boiling-point. This method is applicable

except

for very for all samples except those containing very minute amounts of
TmTunts manganese. In working on spiegel, take .75 gramme, then, using
ofMn- two-thirds of the filtrate, the amount will be calculated on .5
gramme.

Williams' s Method.

This method, which consists in precipitating the MnO2 by
Ford's method, filtering, washing, dissolving in H2SO4 with a
measured volume of some reducing agent, such as oxalic acid
or ferrous sulphate, and titrating the excess by permanganate,
was first used by Williams.* Regarding the precipitate by KC1O3
in a nitric acid solution as MnO2, the reaction in dissolving it
might be expressed thus: MnO2-f- 2FeSO4 + 2H2SO4=MnSO4-r-
Fe2(SO4)3 + 2H2O, or MnO2 + H2C2O4 + H2SO4 = MnSO4 + 2CO2
Oxidizing -f-2H2O. Therefore I molecule of MnO2 oxidizes 2 molecules

power of

MnO2. of ferrous sulphate or I molecule of oxalic acid, and, the excess
of oxalic acid or ferrous sulphate unoxidized having been de-
termined by a solution of permanganate, the difference between
this excess and the amount originally added is the amount
oxidized by the MnO2.

* Trans. Inst. Min. Engineers, x. 100.

RAPID METHODS FOR MANGANESE. 12\

We therefore require two standard solutions, one of perman- standard

solutions

ganate and one of ferrous sulphate, ammonium ferrous sulphate, required,
or oxalic acid. The permanganate solution used for iron deter-
minations answers perfectly. A solution of ferrous sulphate is
perhaps the most satisfactory, and is prepared by dissolving 10
grammes of the crystallized salt, FeSO4,7H2O,* in 900 c.c. water
and 100 c.c. strong H2SO4. It will keep perfectly in a glass-
stoppered bottle in the dark for a long time. One c.c. of this
solution will be equal to about .002 gramme Fe, or nearly .001
gramme Mn, and if the permanganate is of the usual strength,
say I c.c. = .007 gramme Fe, I c.c. of the permanganate will
equal about 3.5 c.c. of the ferrous sulphate. The permanganate standard-
solution having been carefully standardized, measure 50 c.c. of the solutions.
ferrous sulphate solution by means of a pipette into the dish,f
dilute to about I litre, and run in permanganate solution from a
burette, stirring constantly until the first permanent pink tint
appears. The reading of the burette will give the value of 50 c.c.
ferrous sulphate in permanganate, and consequently by a simple
calculation its value in Fe and Mn. Suppose, for instance, I c.c.
permanganate solution = .0068 gramme Fe, or (according to the
proportion given above, 1 12 : 55 : : Fe : Mn) = .00334 gramme Mn.
Then if 14.1 c.c. permanganate = 50 c.c. ferrous sulphate, 100 c.c.
ferrous sulphate will be equivalent to 28.2 c.c. permanganate.
In using oxalic acid, dissolve 2.25 grammes of the crystallized
acid, H2C2O4,2H2O, in I litre of water, and determine its strength
by measuring 50 c.c. into the dish, diluting with hot water,
adding 5 c.c. H2SO4, and titrating with permanganate.

The details of the method are as follows : Weigh out 5 Details
grammes of the sample of puddled iron, pig-iron, or steel, and method.
proceed as directed on p. 116 et seq. ; but after filtering and
washing the precipitated MnO2 with strong HNO3, suck the pre-
cipitate as dry as possible, and then wash out the beaker in

* See page 55. f See Determination of Iron in Iron Ores.

122

ANALYSIS OF IRON AND STEEL.

which the precipitation was made with cold water. Pour this
water on the precipitate, and repeat the operation two or three
times to get rid of all the HNO3. Suck the precipitate as dry
as possible, transfer it with the asbestos to the beaker in which
the precipitation was made, measure into the beaker 100 c.c.
of the standard ferrous sulphate solution (or TOO c.c. oxalic acid
solution and 10 c.c. H2SO4), and stir until the MnO2 is all dis-
solved. When using oxalic acid it is necessary to heat gently
to about 60° C. Wash the solution and asbestos into the dish,
dilute to about I litre (with oxalic acid use hot water), and titrate

with permanganate. We will sup-
FIG. 54.
Example. ^ pose, for example, that it requires

10.2 c.c. permanganate to give the
permanent rose tint; then, as 100
c.c. ferrous sulphate — 28.2 c.c.
permanganate, there would be the
equivalent of 28.2 — 10.2 = 18 c.c.
of permanganate in ferrous sul-
phate oxidized by the MnO2 pre-
cipitate. One c.c. of permanga-
nate being equivalent to .00334
gramme Mn, 18 c.c. = .06012
gramme Mn, and, 5 grammes of
the sample having been taken,
.06012 -5- 5 = .01202 X ioo —
1. 202 per cent. Mn.

Fig. 54 shows a very con-
Apparatus venient piece of apparatus designed by Mr. E. A. Uehling in

for ferrous

sulphate 1 884-*

It is especially useful when it is necessary to rapidly add a
constant volume of a standard reagent, for instance, a measured

* Communicated to the author by Mr. A. L. Colby, of the Bethlehem Iron
Company.

RAPID METHODS FOR MANGANESE. 12$

excess of ferrous sulphate in volumetric determination of man-
ganese after precipitation with potassium chlorate.

The burette-tube extends to the bottom of the Wolff bottle,
which holds 2 litres. Enough air is supplied, without danger of
dust or evaporation of solution, by means of a pin-hole drilled
in the neck of the bottle and through the hollow glass-stopper.
The bottle may be blackened to preserve the solution from the
action of light.

Spiegel and Ferro-manganese.

When working on spiegel or ferro-manganese, take .5 gramme
of the sample and proceed in the same manner as directed for
steel or iron ; but it is better to use a standard solution of ferrous
sulphate containing 30 grammes of FeSO4,7H2O to the litre for
very high ferro-manganese.

As there seems to be some uncertainty as to the exact com- composition
position of the oxide of manganese,* the permanganate solution ideof

may be standardized as follows : Determine the absolute amount
of manganese in a finely-ground and well-mixed sample of spiegel
or ferro-manganese by a gravimetric method, then treat .5 gramme standard-
of the same sample exactly as described above, and, having found spiegei of
the number of c.c. of permanganate that are equivalent to 100 c.c.
of the ferrous sulphate solution, the amount of manganese in the
sample divided by the number of c.c. of permanganate equivalent
to the ferrous sulphate oxidized by the oxide of manganese in
the sample, gives the value of the permanganate solution. Thus,
if 100 c.c. ferrous sulphate solution require 28.2 c.c. permanganate
to give the rose tint upon titration, the sample of spiegel con-
tains 14.50 per cent. Mn, and the ferrous sulphate remaining after
the solution of the oxide of manganese in 100 c.c. requires
6.5 c.c. permanganate to give the rose tint upon titration (using

* Stone, Trans. Inst. Min. Engineers, xi. 323, xii. 295, 514; Mackintosh, Trans.
Inst. Min. Engineers, xii. 79, xiii. 39.

124

ANALYSIS OF IRON AND STEEL.

.5 gramme of the sample, of which i gramme contains .1450
Example. gramme Mn), the calculation would be as follows: 28.2 c.c.—
6.5 c.c. = 21.7 c.c. = .0725 gramme Mn, or i c.c. permanganate
is equivalent to '^jf =.00334 gramme Mn.

Deshays's Method*

This method is based on the fact that nitrate of manganese,
when boiled with excess of nitric acid and peroxide of lead, is
oxidized to permanganic acid, which is reduced again by a
standard solution of arsenite of sodium.

Dissolve .5 gramme of steel or pig-iron in a No. o Griffin's
beaker, or in a test-tube, in 30 c.c. nitric acid, 1.2 sp. gr., and
boil until solution is complete and the evolution of nitrous
fumes ceases. Remove from the burner, and add cautiously 1-3
grammes of dioxide of lead, or red lead, free from manganese,

Washing the and dilute with hot water to about 60 c.c. Heat the solution to
dpitate. boiling, and as soon as it commences to boil stand the beaker
or test-tube aside and allow the lead salt to settle. When tol-
erably clear, decant the solution and boil the residue with 50 c.c.
nitric acid and water (i part acid to 3 parts water). Decant
as before, and repeat the operation until the supernatant fluid is
colorless. Filter the decantations through asbestos and titrate
with a standard solution of arsenite of sodium. The standard
solution may be prepared of a convenient strength by dissolving
4.96 grammes of arsenious acid together with 25 grammes of
carbonate of sodium in water and diluting to 2-2^ litres.

standard- To standardize this solution, treat a steel containing a known

arsenite of amount of manganese, as described above, and calculate the value

solution °f eacn c-c- °f the standard solution by dividing the per cent.

of manganese in the steel by the number of c.c. required to

destroy the color of the permanganic acid. Or take a measured

quantity of a standardized solution of permanganate of potas-

* Bull. Soc. Chim. de Paris, June 20, 1878.

RAPID METHODS FOR MANGANESE. I2

sium and see how many c.c. of the arsenite of sodium are equal
to I c.c. of the permanganate solution. Then the value of the
permanganate solution in iron, multiplied by 11/56 is equal
to its value in manganese, according to the equation,

ioFeS04 + 2KMn04 + 8H2SO4 = 5Fe2(SO4)3 + K2SO4 + 2MnSO4

+ 8H20,

or 10 atoms of Fe correspond to 2 atoms of Mn, or 560 parts
by weight of Fe— no parts by weight of Mn. From this we
get the weight of Mn to which I c.c. of the arsenite of sodium
is equivalent, from which the percentage of manganese in the
steel is calculated.

The details of this method have been very carefully worked
out by Mr. H. C. Babbitt, of the Wellman Steel Company, who Babbitt's
has used it for many years. He finds that ordinary red lead is tions.
quite as effective as the more expensive dioxide, and in an inter-
esting series of experiments he shows that results obtained by
filtering off a portion of the first solution obtained by boiling
with red lead and titrating are not accordant, and that the only
method of getting thoroughly reliable results is by washing out
all the permanganic acid and decanting as described above.

Pattinsoris Method (for Spiegel and Ferro-manganese).

This method is based on the precipitation of manganese as
MnO2, from a solution of MnCl2, by hypochlorite of calcium
and carbonate of calcium in the presence of ferric chloride (the
presence of the latter salt or of chloride of zinc being necessary
to prevent the precipitation of any manganese in a lower state
of oxidation than MnO2).* Dissolve .5 gramme of spiegel or Details
ferro-manganese in a No. 5 beaker in 15 c.c. HNO3, 1.2 sp. gr., method,
evaporate to dryness, and heat to destroy carbonaceous matter.
Redissolve in HC1, and boil down to remove HNO3, but not

* Jour. Chem. Soc., xxxv. 365.

126 ANALYSIS OF IRON AND STEEL.

to dryness, add a few drops of HC1, and dilute with 10 c.c.
water. Add carbonate of calcium diffused in water, until the
solution becomes reddish by neutralization of the free acid, then
add 5 or 6 drops HC1 and 100 c.c. of a solution of bleaching
powder (hypochlorite of calcium), made by treating 15 grammes
of the powder with I litre of water and filtering. Now pour in
about 300 c.c. of boiling water, which will raise the temperature
of the solution to about 70° C., and add carbonate of calcium,
with constant stirring, until all the iron is precipitated. If the
supernatant fluid has a pink color, due to the formation of a
little permanganate, add a few drops of alcohol, which will reduce
it. Filter on a large filter, wash untill the filtrate is free from
chlorides, place the filter and its contents in the beaker in which
the precipitation was made, and add 100 c.c. of standard solution
of ferrous sulphate, made as directed on page 1 2 1. When the
precipitate is dissolved, transfer the solution to the dish, dilute
to about I litre, titrate the excess of ferrous sulphate as directed
on page 121, and calculate the percentage of Mn as there
directed.

The Color Method (for Steel).

This method was first suggested by Pichard,* and was used
essentially in its present form by Peters. f It is now in very gen-
eral use in steel-works, and takes rank with the color carbon
method in its usefulness. It requires one or more standard
steels in which the manganese has been most carefully deter-
mined by a gravimetric method. When a number of samples
are to be tested at the same time, as is usually the case, a bath
like the one shown in Fig. 78 is necessary, but for the man-
Chiondeof ganese color method it should contain a solution of chloride of
bathUm calcium, which boils at 115° C.J It is, of course, very neces-

* Comptes-Rendus Hebd. des S6ances de 1'Acad. des Sciences, Dec. 30, 1872.
f Chem. News, xxxiii. 35.

This latter modification is due to Mr. S. A. Ford.

RAPID METHODS FOR MANGANESE.

127

sary in a method of this kind that the operations should always
be conducted as nearly as possible under the same conditions,
and that the standard should always be dissolved at the same
time as the samples to be tested. Weigh out .2 gramme of
each sample and of the standard, and place them in 8-inch test- method.
tubes properly numbered. Pour into each test-tube 15 c.c.
HNO3, 1.2 sp. gr., cover each with a small glass bulb or very
small funnel, and stand the test-tubes in the holes in the top
of the bath, as shown in the sketch, Fig. 78. Heat in the bath
at 100° C. until solution is complete. Pour the contents of a
test-tube into a 100 c.c. tube, wash the test-tube out with cold
water, adding it to the solution in the 100 c.c. tube, and finally
dilute to the 100 c.c. mark. Mix thoroughly by placing the
thumb over the top of the tube and turning it upside down
several times. Draw out 10 c.c. of this solution with a pipette
graduated to deliver 10 c.c., and let it run into the test-tube in
which the solution was made. Treat each sample in this way,
including the standard. The tube is merely washed out with
water, but the pipette can be best cleaned by drawing it full
from the 100 c.c. tube of the fresh sample, throwing the con-
tents away, and -filling it a second time to deliver into the test-
tube. Stand the test-tubes in the rack again, add to each 3 c.c.
HNO3, 1.2 sp. gr., replace the bulbs or funnels, and stand the
rack in the chloride of calcium bath, the solution in which
should now be boiling. When the solutions in the test-tubes
begin to boil, add to each .5 gramme fine peroxide of lead*
and boil exactly five minutes. The PbO2 can readily be meas-
ured by a small platinum spoon, made to hold about .5 gramme.
It is necessary that the solutions in the test-tubes should boil,

and it is easy to assure one's self of this fact by looking down solutions
into the test-tubes after the action caused by the addition of
the PbO2 has ceased. Remove the rack from the bath at the

* See page 57.

I2g ANALYSIS OF IRON AND STEEL.

expiration of the five minutes, and stand it with the test-tubes
in cold water, to cool the solutions and allow the insoluble lead
salt to settle. The insoluble matter settles to the bottom of
the tube in a heavy compact mass, leaving the supernatant
fluid perfectly clean. When this occurs, which is usually within
the space of half an hour, the solutions are ready to be decanted
into the comparison-tubes.* In working on a number of steels
we will suppose that we use two standards, one containing 1.2
per cent, of manganese, the other .6 per cent. As we weighed
out .2 gramme, diluted the solution to 100 c.c., and took 10
c.c. in which to determine manganese, the amount taken cor-
responds to 0.02 gramme of the sample; and if we dilute the
solutions of the standards after decanting into the comparison-
tubes to 24 c.c., one c.c. will correspond to .05 per cent, in the
high, and .025 per cent, in the low, standard. Decant each
solution in turn into a comparison-tube, -and dilute it until it
Comparing has the exact tint and depth of color of the standard to which

the colors.

it most nearly approximates when first decanted. The per-
centage of manganese is found by multiplying the number of
c.c. to which the sample has been diluted by .05 or .025,
according to the standard with which it has been compared.
If, however, the solution of a sample when first decanted and
before dilution should be lighter in color than the lower
standard, the latter may, after the other samples have all been
finished, be diluted to 30 c.c., when each c.c. will correspond
to .02 per cent, manganese, or, if this color is not sufficiently
light, to 40 c.c., when each c.c. will correspond to .015 per
cent, manganese. When even this color is not sufficiently
light, a lower standard must be used for comparison, or a larger
amount of the sample taken for solution. The comparison of
the colors should be made in a camera or box, as shown in
Fig. 8 1.

* See Fig. 80.

DETERMINATION OF TOTAL CARBON. I2g

The direct rays of the sun should not be allowed to shine
on the solutions, and a northern light for the comparisons is
preferable to any other.

DETERMINATION OF CARBON.

Carbon differs from all other elements in iron and steel in The con-

. ditions

that it is supposed to exist in several conditions, and analytical in which

chemistry supplies the means of distinguishing between at least
two of these conditions. Until within a few years it was con- and
sidered to exist in two forms, as graphite and as combined car-
bon. To Karsten is due the recognition of the fact that graphite
is a form of pure carbon, and not a compound of carbon and
hydrogen. It is always present as a mechanical mixture, and
is thus distinguished from the other form, which was supposed
to be combined chemically with the iron. Of late years the
opinion has been growing that " combined carbon" exists in at
least two conditions in steel, but as yet chemical methods for
separating and distinguishing between these conditions have
failed, so far as quantitative work is concerned. The analytical
methods here given are:

The Determination of Total Carbon,

The Determination of Graphitic Carbon, and

The Determination of Combined Carbon.

DETERMINATION OP TOTAL CARBON.

We may divide the methods for the determination of total
carbon in iron and steel into the following classes :

A. The direct treatment of the borings or drillings without
previous separation of the iron, including :

I. Direct combustion in a current of oxygen (Berzelius).

130

ANALYSIS OF IRON AND STEEL.

2. Combustion with chromate of lead and chlorate of potas-
sium (Regnault).

3. Combustion with oxide of copper in a current of oxygen
(Kudernatsch).

4. Combustion with potassium bisulphate (Bourgeois).

5. Solution and oxidation of the borings in sulphuric,
chromic, and phosphoric acids, the volume of the CO2 being
measured (Wiborg, modified).

6. Solution and oxidation of the borings as in 5, the CO2

•
being weighed.

B. Removal of the iron by volatilization, and subsequent com-
bustion of the carbon, including :

1. Volatilization in a current of chlorine (Berzelius, Wohler).

2. Volatilization in a current of hydrochloric acid gas (Deville).

C. Solution of the iron, and combustion or weighing of the
residue, including:

1. Solution in double chloride of copper and ammonium,
filtration, and weighing or combustion of the residue (Pearse and
McCreath).

2. Solution in* double chloride of copper and potassium,
filtration, and combustion of the residue in oxygen (Richter).

3. Solution in chloride of copper, and combustion of the
residue (Berzelius).

4. Solution in iodine or bromine, and combustion with chro-
mate of lead, or weighing, of the residue (Eggertz).

5. Solution by fused chloride of silver, and combustion of
the residue (Berzelius).

6. Solution of the iron in sulphate of copper, filtration, and
combustion of the residue in a boat in a current of oxygen
(Langley).

7. Solution of the iron in sulphate of copper, and oxidation
of the residue by CrO3 and H2SO4 (Ullgren).

8. Solution in dilute HC1 by the aid of an electric current,
and combustion of the residue (Binks, Weyl).

DETERMINATION OF TOTAL CARBON. l^l

The most accurate method is undoubtedly the solution of the
drillings in the double chloride of copper and potassium and
combustion of the residue in oxygen gas.

A. 1. Direct Combustion in a Current of Oxygen.
This method requires the sample to be reduced to a very fine Necessity

for pow-

state of subdivision, otherwise some of the metal in the centre dermg the

of the lumps becomes coated with oxide, and the carbon in <it

escapes combustion. Weigh out into a porcelain or platinum

boat, about 3 inches (75 mm.) long,* I to 3 grammes of the

sample, and spread it as evenly as possible over the bottom of

the boat. Place the boat in the porcelain tube B, Fig. 61, by Detaas

of the

means of the rod C, replace the stopper P, and turn on a current method.
of oxygen from the cylinder O, the stopcock R being open and
Q closed. The apparatus will now appear as in the cut. The
description of the apparatus is given on page 142 et seq., the
only difference being that for this determination the U-tube H
and roll of silver in the tube B are omitted. The precautions
necessary in weighing the absorption apparatus, consisting of the
bulb I and tube J, are also described fully on page 145. .When
the tube is full of oxygen, the absorption apparatus being weighed
and attached, light the burners in the furnace, beginning at the
forward end, and, when they are all lighted, maintain the tem-
perature of the tube at a good red heat for forty-five minutes.
Should the solution 'in the bulb I begin to recede, owing to the
rapid absorption of oxygen by the metal in the boat, increase
the flow of oxygen, and regulate it so that the gas may never

*I obtained better results by using a platinum boat about 6 inches (150 mm.)
long provided with a cover of platinum-foil, through which a semicircular cut was
made about every y2 inch (12 mm.). On raising these pieces to an angle of 45°
they formed a series of little wings, which directed the current of gas flowing along
the upper part of the tube down into the boat. It is difficult to get a sufficiently
high temperature in a porcelain tube, but the results obtained in a platinum tube were
very satisfactory. (See Jour, of Anal, and App. Chem., 1891, p. 125.)

l$2 ANALYSIS OF IRON AND STEEL,

pass through the bulb I more rapidly than 3 or 4 bubbles in a
second. At the expiration of the forty-five minutes, shut off the
current of oxygen at O, close the stopcock R, open Q, and start
the current of air by opening T gradually, so that the water may
flow into the lower bottle F. Turn down the lights in the fur-
nace slowly, to avoid cracking the tube, finally turn them out,
and allow the current of air to run through the apparatus until
the oxygen is expelled. This will usually be accomplished by
running out half the water in the bottle F. Close the stopcock
T, remove the absorption apparatus, and weigh it. The increase
of weight will be CO2, due to the carbon in the sample, and it
contains 27.27 per cent, carbon.

2. Combustion with Chromate of Lead and Chlorate of

Potassium.

preparation This method, like the preceding one, requires the sample to

combus- be very finely powdered. Take a piece of combustion-tubing

bes' about 32 inches (800 mm.) long, */2 inch (12 mm.) internal

diameter, and ^ inch (1.5 mm.) thick in the walls; heat it in

the middle by means of a blast-lamp until it softens, draw the

ends apart slightly, and then, keeping the ends parallel, draw it

out, as shown in Fig. 55. Allow it to cool, scratch it in the

middle with a file, and
FIG. 55.

break it. This gives

two tubes each about
1 6 inches (400 mm.)
Fuse the laree

ends slightly so as to round the sharp edges, but avoid con-
tracting the tube. Wash the tubes thoroughly, using a rod
with a piece of dark-colored silk or linen on the end ; then if
any lint remains on the inside of the tube it can be easily
seen. Dry the tubes by heating them carefully and drawing air
through them, then fuse the small ends and cork the large ends
to keep out the dust. Weigh out I to 3 grammes (i gramme

DETERMINATION OF TOTAL CARBON.

of pig-iron, spiegel, or ferro-manganese, 3 grammes of steel) of
the sample, and grind it thoroughly in a small mortar with 15
times its weight of fused and powdered chromate of lead and
\y2 times its weight of fused and powdered chlorate of potas-
sium or bichromate of potassium. Bichromate of potassium is
to be preferred, as a little chlorine is sometimes given off by
chlorate of potassium when used in this manner. Place the Details
combustion-tube in a stand, as shown in Fig. 56, and push

133

FIG. 56.

down into the end, with a clean glass
rod, a little ignited asbestos. The
asbestos should not be tightly packed,
as it will prevent the air from passing
in freely at the end of the operation.
Place a small, dry, perfectly clean
funnel in the end of the tube, and
pour through it enough of the pure
powdered chromate of lead to fill the
tube for about one inch of its length.
Hold the mortar under the funnel so
that anything that falls from it may
go into the mortar, and charge the mixture into the tube by
means of a small platinum spatula. Clean out the mortar by
grinding in it two or three successive small portions of chromate
of lead, charging each into the tube through the funnel. Re-
move the funnel, cork the tube, and, holding it in a horizontal
position with the tail up, tap it gently to get a clear space for
the passage of the gas from one end of the tube to the other.
Place the tube in the combustion-furnace, remove the cork, and
insert in its place a smooth velvet cork, through the centre of
which passes one end of a Marchand U-tube. The half of this
tube nearest the combustion-tube contains anhydrous sulphate
of copper,* and the other -half granulated dried chloride of

* See page 53.

134 ANALYSIS OF IRON AND STEEL.

calcium, the two reagents being separated by a small plug of
fibrous asbestos loosely packed. Weigh, and attach the absorp-
tion apparatus and safety-tube. Apply suction at the end of
the rubber tube on the forward end of the safety-tube, and
draw a few bubbles of air through the potash-bulb. Allow the
liquid to recede gradually ; if it maintains its level in the bulb
for a few minutes, the joints of the apparatus may be con-
sidered tight, but if it gradually falls, it is proof that there is a
Testing the leak, and the joints must all be tightened. If, after pushing
of the con- the cork as far as possible into the end of the combustion-
tube and binding all the rubber connections, another trial still
shows a leak, a fresh cork must be substituted. When the
joints are all tight, light the burner at the forward end of the
tube, and each burner successively as the flow of gas slackens,
bringing the tube over each burner to a red heat before lighting
the next one. Maintain the whole length of the tube up to the
asbestos at a good red heat until the flow of gas entirely ceases.
Then pass a piece of rubber tubing attached to a purifying
apparatus well over the tail of the tube, which should be cool
enough to be handled, break the point of the tail inside the
tubing, lower the lights a little, and, by means of the aspirator-

FIG. 57.

bottles, force about I litre of air through the apparatus. It
will now appear as in Fig. 57. Turn out the lights, and de-
tach and weigh the absorption apparatus, with the precautions

DETERMINATION OF TOTAL CARBON. l^

mentioned on page 144. The increase of weight will be the
CO2 due to the carbon in the sample. This contains 27.27 per
cent, carbon.

3. Combustion with Oxide of Copper in a Current of

Oxygen.

Prepare the combustion-tube as directed in the last method, Details

of the

and pour on the asbestos in the end of the tube enough oxide method.
of copper to fill the tube to the height of about an inch (25 mm.).
Mix the weighed sample, I to 3 grammes in a fine state of
division, with at least 20 times its weight of finely-powdered
pure oxide of copper, charge it into the tube as directed on page
133, rinse out the mortar with a little more of the same material,
and finally fill the tube to within an inch (25 mm.) of the end
with granulated oxide of copper. Make the combustion exactly
as directed in the last method, page 1 34. If the combustion is Using a
to be made in a current of oxygen, which is much the best plan, oxygen,
instead of drawing the combustion-tube out to a point and sealing
it, it may be drawn out straight, as shown in Fig. 58. In this
FIG. 58. case, attach to the drawn-out end

U ^-^^ when the tube is in the furnace a

purifying apparatus for oxygen and air, as shown in Fig. 61, and
conduct the operation as directed on page 131.

4. Combustion with Potassium Bisulphate.

Certain classes of special material, such as ferro-chrome,
cannot be decomposed by any solution, nor can the carbon be
determined by direct combustion in oxygen.

The only known method is by fusion with potassium bisul-

phate. Method for

Weigh I gramme of the finely-powdered sample into a
porcelain boat about 150 mm. long, 25 mm. high, and 30 mm.
wide, and mix intimately with 30 to 40 grammes of fused
powdered potassium bisulphate. Place the boat in a porcelain

136 ANALYSIS OF IRON AND STEEL.

tube arranged as in Fig. 61. Connect the tube at the forward
end with a flask containing a mixture of sulphuric and chromic
acids, which can be heated. Connect with this a U-tube con-
taining pumice saturated with chromic acid, then U-tubes, G
and H, Fig. 61, filled as described on page 144. Attach the
absorption apparatus and heat the forward end of the porcelain
tube containing the oxide of copper, and warm the flask con-
taining the sulphuric and chromic acids. Heat the tube where
the boat is very gently for two hours and gradually raise the heat
to dull redness for half an hour, continuing the passage of the
oxygen. Shut off the oxygen and pass the air for 20 minutes.

Weigh the absorption apparatus in the usual way. The
liberated sulphurous acid is oxidized by the oxide of copper or
the chromic acid, and only the carbonic acid finds its way into
the absorption apparatus.

5. Solution and Oxidation of the Borings in Sulphuric,

Chromic, and Phosphoric Acids, the Volume of

the CO2 being1 measured.

The method given below for the determination of carbon in
steel is generally used in the steel works laboratories in the
eastern part of France, and I am indebted for the details to
Monsieur H. A. Brustlein of Jacob Holtzer & Cie, of Unieux,
at whose works and at those of the Acieries de la Marine at
Saint Chamond the various improvements in the method have
been worked out.

The method was first suggested by Wiborg,* but was very
imperfect in its original form. The greatest improvement was
suggested by Monsieur de Nolly, of the Laboratory of the
Acieries de la Marine at Saint Chamond, and consists in the
addition of phosphoric acid to the oxidizing mixture, by which
the iron is much more rapidly dissolved and the use of a con-

* Stahl und Ei<en, 1887, p. 465.

DETERMINATION OF TOTAL CARBON. l^

siderable amount of chromic acid is rendered possible without
the evolution of a large volume of oxygen gas. M. Benazet
and M. Florence, of Unieux, substituted mercury for water in
the original method.

The solutions employed are:

1. A saturated solution of chemically pure cupric sulphate.

2. An aqueous solution of chromic acid (i gramme chromic
acid to i c.c. water).

3. A mixture of sulphuric, phosphoric, and chromic acid
made up as follows :

Solution of chromic acid (Sol. No. 2) 35 c.c.

Water 190 " Solutions

Concentrated sulphuric acid 75° " required

Phosphoric acid 1.4 sp. gr 340 "

In preparing solution No. 2, add a few c.c. of sulphuric acid
and heat to boiling to destroy any organic matter that may be
present.

In preparing solution No. 3, heat it to boiling also for the
same purpose.

The apparatus as shown in the sketch consists of a round-
bottom flask, A- of 250 c.c. capacity, with a long neck. The
flask is closed with a rubber stopper with two holes, in one of
which is fitted the glass stopper funnel B and in the other the
tube C enclosed in the condenser D, through which a stream of
water runs during the operation. The tube C is connected with
one tube, E, of a three-way stopcock, a, from which the second
tube, F9 opens into the air and the third, G, connects with the
tube H of the three-way stopcock b. The second tube, Jt from
this stopcock is fused to the burette K. which is enclosed in the Description

of the

tube L containing water. The lower end of the burette connects apparatus,
with a tube, M, of small interior diameter, which serves as a level
tube and is in the form of a T ; it is connected with the mercury
reservoir N, which is raised and lowered by the arrangement 0.
The third tube of the stopcock b connects with the tube P of

138

ANAL YSIS OF IRON AND STEEL.

the stopcock c, the second tube, Q, of the stopcock c connects
with the manometer R, and the third tube, S, with the pipette
T, which runs into the bottle U. The tubes of the stopcocks b

FIG. 59-

and c, the manometer tube R, the level tube M, and the tubes of
the pipette T are capillaries. The manometer tube R contains
water, and serves to accurately adjust the levels when taking the

DETERMINATION OF TOTAL CARBON.

reading of the burette K. When the manometer is shut off
from the burette the approximate level is ascertained by means
of the level tube M. The tube F of the stopcock a is used only
in exceptional cases : First, when the evolution of gas is insuffi-
cient to carry the mercury far enough down the burette K, in
which case air is drawn through it into the burette ; and secondly,
when the evolution of gas is so great that it is necessary to make
two absorptions in the pipette T, in which case the residue from
the first absorption is discharged through the tube F. The
pipette T contains a solution of potassium hydroxide of 1.27
sp. gr., it is of about 400 c.c. capacity. The bottle U is of about
one litre capacity. The water in the containing tube L serves to
keep the gas in the burette at the ordinary temperature of the
laboratory. It should be protected from the heat of the burner
and flask by a screen.

The operation is conducted as follows :

Connect the pipette T, by means of the stopcocks b and c,

with the burette K and, by lowering the mercury reservoir, fill The opera-
tion.

the pipette with the potassium hydroxide solution, close the stop-
cock c, fill the burette K with mercury, and close the stopcock b.
Weigh i gramme of drillings into the flask A, attach it to the
apparatus, start the water through the condenser D, and con-
nect the flask with the burette K by means of the stopcock a.
Pour fifteen c.c. of the cupric sulphate solution No. I into the
funnel tube B, and let it flow into the flask. Allow it to act
long enough to form a superficial deposit of copper on the
drillings (one or two minutes is sufficient), then add,- through
the funnel tube, fifteen c.c. of solution No. 2 and 135 c.c. of solu-
tion No. 3. Heat the solution in the flask and raise it slowly to
the boiling-point. By means of the reservoir, keep the mercury
in the burette and in the tube M nearly level. The water con-
densed in the tube C drops back into the flask and keeps the
liquid of the same density, while the properly cooled gases pass
into the burette.

140

ANAL YSIS OF IRON AND STEEL.

Calculation
of the
results.

Description
of the
apparatus ,

Allow the flask A to cool for about five minutes, and then
run into it, through the funnel tube B, enough water to fill the
flask and the tube to the stopcock a, thus forcing all the gas
into the burette. Close the stopcock a and connect the burette,
by means of the stopcocks b and c, with the manometer R, adjust
the levels accurately, and take the reading of the burette. Then
by means of the stopcock c connect the burette with the pipette
T and, by raising and lowering the reservoir Nt pass the gas
several times back and forth to cause the potassium hydroxide
to absorb all the carbon dioxide. Finally connect the burette
with the manometer tube R, adjust the levels, and take the
reading of the burette.

The burette K should contain a few drops of water to insure
the saturation of the gases with aqueous vapor. The difference
between the two readings is the volume of the carbon dioxide.
Observe the readings of the thermometer and barometer and
reduce the volume of the carbon dioxide to that which it would
occupy in the dry state at o° C. and 760 mm. pressure. (Table V.)

Multiply the volume of the gas so obtained by 0.0019663, and
the result is the weight of the carbon dioxide in grammes.

6. Solution and Oxidation of the Borings as in 5, the CO2

being weighed.

Fig. 60 shows the details of the apparatus for carrying out
this method. M is the U-tube for purifying the air. It contains
fused caustic potassa. A is the flask for oxidizing and dissolving
the sample. The piece of glass tubing TV bent at a right angle
is drawn out slightly at the lower end, over which a piece of
soft gum tubing is fitted, forming a stopper, which fits tightly in
the top of the bulb-tube when air is forced through the appa-
ratus. B is a bulb-tube for introducing the reagents. The lower
end is drawn out so that the orifice is quite small. 0 is a con-
denser, P contains anhydrous cupric sulphate, Q granular chloride
of calcium, and the small bulb of P and Q contains cotton-wool.

DETERMINATION OF TOTAL CARBON.

141

142 ANAL YSIS OF IRON AND STEEL.

The Liebig bulb and the tube R form the absorption apparatus,
and 6* the safety-tube. Conduct the operation as described on
page 139, pass two litres of air through and weigh the absorp-
tion apparatus as described on page 146.

B. 1. Volatilization of the Iron in a Current of Chlorine, and
Subsequent Combustion of the Carbon.

Weigh out i gramme of pig-iron or 3 grammes of steel into

a porcelain boat about 3 inches (75 mm.) long, and treat it ex-

*actly as described on page 73 et seq. The boat when withdrawn

from the tube contains the carbon, slag, and oxides, and nearly

all of the non-volatile chlorides, such as MnCl2. When the

sample contains much manganese, it is necessary to treat the

residue in the boat with cold water, filter it on a small plug of

ignited asbestos, return it to the boat, and dry it before burning

This method it off. As this adds very considerably to the time required for

not suit-
able for the determination, it is best to adopt some other method for

Inchferro- the determination of carbon in such materials as spiegel and
ferro-manganese. Introduce the boat into the tube B of the
Description apparatus, Fig. 61. This apparatus consists of a ten-burner
combus- combustion-furnace A, through which runs the porcelain tube
ratus*1*1 B. This tube is about 25 inches (625 mm.) long, and ^ inch
(18 mm.) internal diameter. It projects 6 inches (150 mm.)
outside the furnace at each end, and the sheet-iron screens L
prevent the heat from reaching the stoppers P and S. The
Preparation tube is filled for a length of 6 inches (150 mm.), or from about
ideofcop- the middle of the tube to the forward end of the furnace, with
oxide of copper, which is best made by rolling up tightly a
piece of coarse copper gauze 6 inches (150 mm.) long until it
makes a roll nearly filling the bore of the tube, and heating it
Ron of for an hour in a current of oxygen. A piece of thin sheet-
silver 4 inches long, and forming a roll completely filling the
bore of the tube, is placed just in front of the oxide of copper:
it serves to absorb any chlorine given off during the combus-

DETERMINATION OF TOTAL CARBON.

ANALYSIS OF IRON AND STEEL.

tion.* A roll of copper gauze 2 inches long, with a loop in
one end, thoroughly oxidized, is pushed in after the boat con-
taining the carbon. The cylinder O contains oxygen under
Air. pressure. The bottles F, F serve to force air through the

apparatus to replace the oxygen at the end of the operation.
The stopcock T serves to regulate the flow of water, and con-
sequently of air. When all the water has run from the upper
into the lower bottle, it is siphoned out of the latter and re-
turned to the former.

Purifying The purifying apparatus M and N, for oxygen and air respec-

for oxygen tively, consist of Liebig potash-bulbs filled with caustic potassa,
1.27 sp. gr., and U-tubes, the sides next the potash-bulbs filled
with dry pumice, and the other sides with chloride of calcium.
The glass stopcocks Q and R shut off the purifying apparatus on
their respective sides when the oxygen or air is passing through
the other set. The T-tube D connects the two sets of appa-
ratus, the third limb passing through the glass in the side of
the hood, and connecting by means of the bent-glass tubes with
the rubber stopper P, which fits in the porcelain tube B. All
Danger of the connections are made with glass tubes joined together by
her tubes, rubber tubing, the ends of the glass tubing being brought close
together inside the rubber. This is to avoid carrying the oxygen
or air through rubber tubing, which gives off volatile hydro-
Drying and carbons. The Marchand U-tube G contains anhydrous sulphate
apparatus °f copper to absorb any HC1 which may be evolved during the
Asbestos* combustion. It is joined to the tube B by a rubber stopper or
stopper. kv an asbestos stopper,f made by pressing wet fibrous asbestos
into a mould of the proper shape. When sufficient pressure is
applied in making the stopper it becomes very hard. When dry
it can be bored easily, and makes an excellent stopper for this
purpose. The U-tube H contains granulated dried chloride of

* This roll of silver must be occasionally removed and ignited in a current
of hydrogen to remove the chlorine.

f J. F. White, Amer. Chem. Jour., iii. 151.

DETERMINATION OF TOTAL CARBON. l^

calcium.* The absorption apparatus consists of the Liebig bulb Absorption
I and the drying-tube J. I contains caustic potash, 1.27 sp. gr.
It is filled by attaching a short piece of rubber tubing to one
end and applying suction to it, the other end being immersed
in the potassa solution, which has been poured into a capsule.
The end must be wiped dry with a little filter-paper, and the
inside of the tube dried in the same way. When filled, the bulb
should contain the solution as shown in Fig. 62. When attached
to the apparatus, the gas passes first into F

the large bulb, and, the bulbs being in-
clined, the gas bubbles through the solu-
tion in the three bottom bulbs. It is
fitted with a loop of platinum wire, as
shown in Fig. 62. The drying-tube J
contains dried chloride of calcium. The
small bulb a, Fig. 61, contains a plug of
cotton-wool, and another plug of the same
material is inserted after the chloride of
calcium at b. K is a safety-guard tube, Safety-guard

to prevent moisture from getting into the tube J during the com- tube'
bustion. The short rubber tube V is used to draw a little air
through to test the tightness of the joints. All the stoppers in
the various U-tubes and drying-tubes are of rubber. The copper
rod C is used to introduce the boats, etc., into the tube B, run-
ning the crooked end through the hole W in the glass side of the
hood. When not attached to the apparatus, the ends of the
potash-bulb I and drying-tube J are closed by little caps of rubber
tubing f (Fig. 62) made like the tips for " policemen." When on
the balance, however, they should be closed with short pieces
of rubber tubing containing bits of capillary glass tubing, as
shown in Fig. 63. The forward end of the drying-tube is closed
in the same way. These openings are too small to allow the

* See page 52. f See page 31.

ANALYSIS OF IRON AND STEEL.

condition of the atmosphere to affect the weight of the bulbs by
loss or gain of moisture, but they serve to equalize the pressure
FlG 6- and make it unnecessary to

reopen the balance-case until
the bulbs are weighed.

Precauti°ns /A^r^x Jt is very necessary in

m weigh- 7Hi V^\

insthe ///If ) filling the potash-bulb to

absorp- W V /

avoid getting any of the
solution on the outside of

the bulb, and it is well to
see that both the bulb-tube
and the drying-tube are per-
fectly clean. Wipe off the
potash-bulb and drying-tube
with a piece of linen, not
silk (a clean linen handker-
chief that does not leave lint on the glass is very good for this
purpose), and place them on the balance.

The little wire stand shown in Fig. 63 is very convenient for
holding the absorption apparatus in the balance, as it brings all
the weight on the pan instead of putting the greater part on the
beam alone, as is the case when the potash-bulbs are suspended
from the hook on the end of the beam. The latter arrangement
puts more weight on one pan than on the other, thus throwing
the needle out of the vertical. Allow them to remain about
thirty minutes to get the exact temperature of the balance, and
Details of weigh. Attach the absorption apparatus as shown in the sketch,

the com-
bustion. Fig. 6 1, insert the boat in the tube by means of the rod C, push-
ing it up against the oxide of copper, insert the short roll of
oxidized gauze as far as the inside of the screen L, and close the
tube with the stopper P. Shut the stopcocks R and Q, and, by
applying suction at V, draw a few bubbles through the potash-
bulb I. When the liquid recedes in the potash-bulb, it should
keep its level for a few minutes ; if it does not, there is a leak in

DETERMINATION OF TOTAL CARBON. 147

some of the connections, which must be discovered and stopped
before proceeding with the combustion. When everything is
tight, open R and start a slow current of oxygen through the
apparatus. Light the two forward burners of the furnace, turning
them low to heat the oxidized copper gauze, raise the heat grad-
ually until the tube appears red, and then light the last burner
to heat the short roll of oxidized copper gauze. As soon as
this end of the tube is hot, light the third burner from the
forward end, and a few minutes afterwards the fourth burner,
which is directly under the forward end of the boat. Light
each burner in succession from this one until all are lighted
and turned high enough to heat the tube red-hot. Allow them
to burn for fifteen minutes, then shut off the oxygen, close R,
open Q, and by means of the stopcock T start a current of
air through the apparatus. By means of the gas-cock X lower
all the lights of the furnace together very slowly, to avoid
cracking the tube, and finally turn them out. About I litre
of air should run through at the rate of about 3 bubbles a
second; this will about half empty the upper bottle L. Close
T and Q, detach the absorption apparatus, close the ends of I
and J with the little rubber caps, and, after wiping the bulb and
tube gently with the linen handkerchief to remove any moisture
caused by the handling, place them on the balance. Weigh
with the same precautions as before ; the increase in weight is
CO2, which contains 27.27 per cent, carbon. When several com- when
bustions are to be made in succession, as soon as the absorption "number
apparatus is detached as directed above, remove the boat from
the tube, replace it with another containing a second sample,
attach a second absorption apparatus which has just been
weighed, and proceed with the combustion. While the second
combustion is in progress, the first absorption apparatus may be
weighed, and the weight then obtained can be used for the first

weight of the absorption apparatus for a third combustion. Be- ins KHO

solution

fore the absorption apparatus shall have increased .5 gramme frequently.
in weight from the original weighing, the potash-bulb must be

148

Condition

when Lt

in use.

Tube to be
before

obtained

in very

damp,
weather,

Apparatus

ANAL YS2S OF IRON AND STEEL.

emptied and refilled with a fresh solution. When the final com-
bustion for the day is finished, place a piece of glass rod in the
open end of the connection of H, remove the boat from the
tube B, replace the short roll of oxidized copper gauze in the
tube, insert the stopper P, but not tightly, open R and Q, and
loosen the stopper in the bottle F. Place pieces of glass rod
in the ends of the safety-tube K, to prevent access of moisture.
Whenever the apparatus has been out of use for a day, before
making a combustion or set of combustions remove the piece
of glass rod from the forward end of the U-tube H, insert in its
place a piece of glass tubing drawn out at the forward end to a
small orifice, start a current of oxygen through the apparatus, light
the burners in the furnace, raising the heat very gradually, keep
the tube at a red heat fifteen minutes, turn off the oxygen, start
the air, lower the burners gradually, and pass a litre of air through
the apparatus. It will then be ready for the combustion. In
very damp weather it is almost impossible to get good results, the
condensation of moisture on the absorption apparatus rendering
the weighing extremely difficult even when the utmost care is used.

2. Volatilization of the Iron in a Current of Hydrochloric
Acid Gas, and Subsequent Combustion of the Carbon.

The process is exactly the same in this method as in that just
described, a current of hydrochloric acid gas being substituted
for one of chlorine. The apparatus for generating this gas is the
same as the one used for chlorine, common rock-salt in pieces
about as large as a filbert being substituted for binoxide of man-
ganese, and sulphuric acid, diluted with two-thirds its bulk of
water, for hydrochloric acid.

C. 1. Solution in Double Chloride of Copper and Ammonium,*
Filtration, and "Weighing or Combustion of the Residue.

Weigh i gramme of pig-iron, spiegel, or ferro-manganese into
a No. 2 Griffin's beaker, and add 100 c.c. of saturated solution of

The potassium salt is now in general use and is preferred by most chemists.

DETERMINATION OF TOTAL CARBON.

149

the double chloride of copper and ammonium* and 7.5 c.c. HC1.
For steel or puddled iron, weigh 3 grammes f into a No. 3 beaker,
and add 200 c.c. of the double chloride of copper and ammonium
solution and 15 c.c. strong HCL Stir the solution constantly with
a glass 'rod for some minutes at the ordinary temperature. The
more it is stirred the more rapid will be the solution of the iron Solution
and of the precipitated copper. The beaker, carefully covered, sample,
may now be placed on the top of the air-bath or on a cool part
of the sand-bath, but the solution should never be heated hotter
than 60° or 70° C, and it should be stirred as often as practicable.
As the most tedious part of the determination of carbon in
steel is frequently that which has to do with the decomposition
of the steel and the solution of the precipitated copper, particularly
with low steels, the samples being nearly always in lumps, and the
analyst does not wish to separate these larger particles for fear
that the fine stuff alone may not represent a true average, the

FIG. 64.

0 0 ..U
73

machine shown in Fig. 64 is very useful. It consists of a frame-
work A of brass, cast in one piece for the sake of rigidity. It is
fastened to the table by lugs and screws not shown in the cut.

* See page 54.

f See page 37, " Factor Weights."

150

ANAL YSIS OF IRON AND STEEL.

Description
of stirring-
machine.

The shelf, on which the beakers stand, has on it a piece of asbestos
board with holes to fit exactly the bottoms of the beakers to pre-
vent them from moving. To further increase the stability of the
beakers (which should be of very heavy glass) their bottoms are
ground on a glass plate with fine emery until they have a good
bearing surface all around.

The tops, which are covered when on the machine with a
plate of glass, F, ground on one side and perforated to allow the
passage of the stirring-rods E, are likewise ground, so that when
slightly moistened the ground glass prevents almost entirely all
movement of the covers on the beakers when the machine is in
motion.

The small wooden pulleys C are fitted with brass spindles,
which run through the upper cross-piece and have on their lower
ends pieces of rubber tubing, which serve to hold the stirring-rods.
The stirring-rods are bent as shown in the cut, to give the proper
motion to the liquid. A small motor, B, adapted to the strength
of the current, furnishes the requisite power. The motor, if
properly wound, may be attached to an ordinary incandescent
lighting current, but a sewing-machine motor run by a dipping
battery of three bichromate cells is sufficient to give the necessary
number of revolutions.

Necessity The fact that it is not only unnecessary to use a neutral so-

latingthe lution, but that the use of a neutral solution gives inaccurate
solutlon- results, seems now to be thoroughly established by the experi-
ments of the American members of the International Steel
Standard Committee. The best practice is to add about 10 per
cent of HC1 to the solution of double chloride. The reactions
occurring may be considered as Fe -f CuCl2— FeCl2 -f- Cu and
Cu + CuCl2 = 2CuCl. The part taken by the chloride of am-
monium does not seem very clear, but the fact remains that
the precipitated copper is much more soluble in the double
chloride of copper and ammonium than in any other menstruum.
When the precipitated copper is all, or very nearly all, dis-

DETERMINATION OF TOTAL CARBON.

FIG. 65.

solved, which is usually the case in half an hour after the so-
lution of double chloride of copper and ammonium is added to
the drillings, run a little
of the acidulated double
chloride by means of the
rod around the sides of
the beaker, wash off the
rod into the beaker with
a jet of water, and let
the beaker stand for a
few minutes to allow the
carbonaceous matter to
settle.* The best form
of filtering-apparatus is
shown in the annexed
sketches. It consists of
the perforated platinum
boat (Fig. 65), which fits in the platinum holder. To prepare
the boat for use, place it in the holder, as shown in Fig. 66,
attach the pump, but do not start it. Fill the boat with pre-
pared asbestosf- suspended in water, pour enough around the
outside of the boat to fill the space a, Fig. 66, and start the
filter-pump. Continue pouring the suspended asbestos into the
space a, Fig. 66, until enough is drawn into the joint to make
a good packing. By pressing it in all round with a spatula
the joint may be made very tight. Pour enough of the sus-
pended asbestos into the boat to make a good, thick felt, and
.press it down firmly all over the bottom of the boat with
something like the square end of a lead-pencil, to make it
compact. Detach the pump, remove the boat from the holder
carefully so as to leave the packing on the sides of the holder,

* Barba suggests adding to the solution ignited asbestos in water to make the
carbonaceous matter settle and to prevent its clogging the filter. This is a most
admirable suggestion and should be generally adopted. f See page 26.

Filtering on
perforated
platinum
boat.

Method of
preparing
the boat.

152

ANAL YSIS OF IRON AND STEEL.

and move it up with the end of a spatula, so that it will re-
main as shown in Fig. 65. Place another boat in the holder,
press the packing into the joint a, Fig. 66, with the end of a
spatula, fill the boat with suspended asbestos, and start the

FIG. 66.

pump. If necessary, pour a little of the finer suspended as-
bestos fibre into the joint to make it perfectly tight, and pre-
pare the felt in the boat as before. Dry the boats, and ignite
them in the combustion-tube, two at a time, in a current of
oxygen. Fit one of these prepared boats in the holder, press
the packing into the joint as before, first moistening it slightly
if it has become dry, start the pump, and pour into the boat
enough suspended asbestos, which has been ignited in oxygen,

DETERMINATION OF TOTAL CARBON.

to form a thin film on the top of the felt. This film will hold
the silica, phosphate of iron, etc., from the carbonaceous resi-
due, and, after the combustion, will usually turn up at the edges,
so that it can be readily detached from the main felt, leaving
the boat ready for another filtration.

The boat being thus prepared, pour into it the solution of the
iron or steel, guiding the stream by a small glass rod held against pared
the tip of the beaker. The solution, if the joint a, Fig. 66, is
tight, and the pump works well, will usually run through the felt
as rapidly as it can be poured into the boat. When the super-
natant fluid has all run through, transfer the carbonaceous matter
to the boat by a fine stream of cold water from a washing-flask.
Pour into the beaker about 10 c.c. of dilute hydrochloric acid, run
it all around the inside of the beaker by means of the rod to dis-
solve any adhering salt, wash off the glass rod and wash down
the sides of the beaker with a jet of water, and decant the acid into
the boat, filling the boat almost up to the edge. Wash the car-
bonaceous matter in the boat thoroughly with hot water by filling
the boat from the beaker and allowing it to suck through dry,
but do not attempt to throw a jet of water into the boat from the
washing-flask, as.it will be almost certain to throw some of the
carbonaceous matter from the boat or cause it to crawl over the
side. In decanting the water from the beaker, the lip must not
be allowed to touch the surface of the liquid in the boat, as a
film of carbonaceous matter will run up the inside of the beaker.
Pour a little dilute acid into the joint between the boat and holder,
allow it to suck through the packing, and wash it several times
with hot water. The carbonaceous matter from pig-iron, pud- Differences
died iron, spiegel, ferro-manganese, and ingot steel usually washes filtration
like sand, but that from steel which has been hardened, tempered,
hammered, or rolled is apt to be more or less gummy, stopping
the filter and rendering the filtration and washing prolonged and
tedious. It is also apt to adhere more or less to the sides of the
beaker, and must be wiped off by a little wad of ignited fibrous

154

ANAL YSIS OF IRON AND STEEL.

FlG

FIG. 68.

asbestos, held in a pair of platinum-pointed forceps like those
shown in Fig. 67. This wad is then placed in the boat. When

the carbonaceous matter is
thoroughly washed and
sucked dry, detach the pump,
remove the boat from the holder, wipe it off carefully with a piece
of silk, place it in a dish covered with a watch-glass, and dry it
in a water-bath or in an air-bath at 100° C. When dry, insert
the boat in the tube (Fig. 61), and burn off the carbon as directed
Platinum on page 146. Instead of the porcelain tube, a platinum tube of

combus- IT • i • -.—. /-

tion-tube. the dimensions shown in Fig. 69 may be used to very great advan-
tage. The rear end has a ground joint (Fig. 68), which may be

made perfectly air-tight. The tube has
a strengthening band of German silver at
B, Fig. 69, and the part P, which is of
phosphor-bronze, is ground in. To pre-
vent the tube from sagging when it is

hot, the rear end is supported at P, Fig. 69, by a wire from the
top of the hood. A piece of platinum gauze ^ inch long (12
mm.), rolled up rather loosely, fills the forward end of the tube,
then the tube is filled for a distance of about 6 inches (150 mm.)
with granular oxide of copper, followed by another piece of plat-
inum gauze of the same size as the first, and a similar roll 2 inches
long, with a loop, is pushed in after the boat, the rear end coming
just forward of the screen L. The limb of the U-tube G nearest
the platinum tube contains anhydrous cupric sulphate* and the
forward limb anhydrous cuprous chloride.f H contains dried, not
fused, chloride of calcium, and in the bulb next to G is a small
wad of cotton-wool, which should be moistened with a single drop
of water before each set of combustions. G and H are called the
purifying train, and when the apparatus is not in use they should
be detached from the tube and the ends closed with pieces of

The purify-
ing train.

* See page 53.

f See page 53.

DETERMINATION OF TOTAL CARBON.

155

ANALYSIS OF IRON AND Sl^EEL.

glass rod. The object of the cuprous chloride is to absorb any
chlorine that may come over during the combustion. If any
should come over it would be mixed with hydrochloric acid and
moisture, and all then would be absorbed by the salts in the tube
G. If the carbonaceous residue is properly washed it will be
found necessary to renew the salts in G only after it has been
used for 25 or 30 combustions.*
Necessity for Before making a combustion, or series of combustions, the

burning

out the tube should be well burned out by heating it to redness and pass-
fo^mak. ing a current of oxygen through the apparatus, heating the small
bMdon°m" tuke S reci-hot at the same time by means of a small blast-lamp
or Bunsen burner. During this operation fumes of sulphuric acid
issue from the end of S, and usually, when the flame of the lamp
is carried out to this point, it is colored green, showing that a
small amount of copper salt is also volatilized. In making a
combustion the platinum should not be heated above a low red,
as at a high temperature platinum becomes permeable by CO2.
The burners in the furnace should be lighted in the order directed
on page 137, and, after they are all lighted, ten minutes are ample
to burn off the carbonaceous matter in the boat. From the time
of putting in the boat, fifty minutes are ample for finishing the
combustion, including the displacement of the oxygen by air.

Instead of the arrangement of bottles F, F for forcing air
Cylinder through the apparatus shown in Fig. 61, a second cylinder con-

of com-
pressed taining air under pressure, as shown in Fig. 69, is much more sat-
isfactory, as the current can be controlled with perfect accuracy,
the trouble of siphoning the water from the lower bottle is
avoided, and there is no danger of passing gases or fumes from
the laboratory into the apparatus.

The time required when using a porcelain tube is somewhat
longer, owing to the danger incurred of cracking the tube if the

* For a detailed account of the experiments on determination of carbon in steel
see Prof. Langley's paper, Transactions of the Inst. of Mining Eng., Pittsburg Inter-
national Meeting, October, 1890, and Jour, of Anal, and App. Chem., 1891, page 121.

air.

DETERMINATION OF TOTAL CARBON. 157

heat is increased or diminished too rapidly. A platinum tube
shorter than the one here figured is not to be recommended, as
it cannot contain enough oxygen to burn the carbon to CO2, and
a consequent loss is often unavoidable. Duplicate results by this
method should rarely vary more than .005 of a per cent, carbon.
When using 3 grammes of the sample, the percentage of carbon
is obtained by dividing the weight of CO2 by 1 1 and multiplying
by 100.

Instead of the perforated boat and holder described above, Filtering in

. a platinum

the carbonaceous residue may be filtered in a small platinum filtering-
tube fitting inside the combustion-tube. It is made as represented
in Fig. 70. The small perforated disk of platinum rests on a seat
in the tube as shown in the sketch. The felt in the disk p1G> 7a
is prepared in the same way as directed for the boat,
and, after drying the carbonaceous residue, the disk is
moved upward in the filtering-tube before inserting the
latter in the combustion-tube, to allow the gas to pass
through the filtering-tube during the combustion. The
boat has several advantages over the filtering-tube, the
principal one being that the boat has a much larger filtering-sur-
face, and, besidesr there is no danger of the felt being disturbed
during the filtering, while the disk in the tube may be loosened
in its seat and allow some of the carbonaceous matter to pass
around it. If the boats when not in use are kept carefully
covered, the same felts may be used for a large number of
filtrations; but occasionally they become clogged, and then it is
better to renew them.

Instead of either of these forms of filtering-apparatus, a sim- Glass filter-
pie glass tube, as represented in Fig. 71, may be used. The
closely-coiled spiral of platinum wire fits in the tube as shown
in the sketch. On this is placed a rather thick layer of ignited
long-fibre asbestos, and ignited asbestos suspended in water is
poured over it to make a solid felt. The tube may be used in
a stand, as represented in Fig. 72, or it may be used with the

158

ANALYSIS OF IRON AND STEEL.

filter-pump under very gentle pressure. Filter and wash the
carbonaceous matter, and while still moist transfer it to the boat

FIG. 71.

FIG. 72.

(Fig. 73) by opening out the sides of the boat, inverting the tube
over it, and allowing the felt and spiral to slide out of the tube.
Wipe off any carbonaceous matter that may remain on the sides

FIG. 73-

Boats of
platinum-
foil.

of the tube, or that may have adhered to the spiral in removing
it, with little wads of fibrous asbestos held in the forceps (Fig. 67).
Place these wads in the boat, bend the sides of the latter into

DETERMINATION OF TOTAL CARBON.

159

their proper shape, dry the boat and contents at 100° C, insert
the boat in the porcelain or platinum tube, and burn off the
carbonaceous matter as before directed. This boat is made by
cutting a piece of platinum-foil in the shape shown in Fig. 74,
and bending it up over a brass former into the shape shown

in Fig. 73.

FIG. 74-

Instead of burning the carbonaceous matter in a current of combustion

oxygen, it may be burned by H2SO4 and CrO3 in the arrange-
ment shown in Fig. 75. P' is an empty U-tube, O is a tube
containing sulphate of silver dissolved in strong H2SO4, P con-
tains anhydrous sulphate of copper, Q granular dried chloride
of calcium,* the Liebig bulb and drying-tube R constitute the
absorption apparatus, S is the safety-guard tube, and L, L con-
stitute the arrangement for passing air through the apparatus.
The air is freed from CO2 in passing through the U-tube M
filled with lumps of fused caustic potassa. Transfer the carbo-
naceous matter and asbestos to the flask A, insert the stopper
carrying the bulb-tube B, close the stopcock C, and connect
the apparatus as shown in Fig. 75, including the weighed ab-
sorption apparatus. See that the joints are all tight, and then
pour into B 10 c.c. of a saturated solution of chromic acid, ad-
mit it to the flask A by opening the stopcock C, and then pour

of the

residue

inCrO8

and

H2S04.

* The bulb of Q contains a wad of slightly moistened cotton-wool, as described
on page 137.

i6o

ANALYSIS OF IRON AND STEEL.

DETERMINATION OF TOTAL CARBON. l^l

into B 100 c.c. strong H2SO4 which has been heated almost to
boiling with a little CrO3. Let this run into A slowly, connect
the air-apparatus by the tube N, and start a slow current of air
through. Light a very low light under A, and increase it grad-
ually until the liquid is heated to the boiling-point. Gradually
lower the light while the current of air continues to pass, and
when about I litre of air has passed through the apparatus after
the light is extinguished, detach and weigh the absorption ap-
paratus, with the precautions mentioned on page 146.

The carbonaceous residue may also be weighed directly in- weighing
stead of being burned off. In this method, filter on a Gooch residue*
crucible or on counterpoised filters,* dry at IOO° C, and weigh.
Burn off the carbonaceous matter and weigh the residue : the
difference between the two weights is carbonaceous matter, which
contains about 70 per cent, of carbon f in steel or iron free from
graphite. Of course this method of direct weighing is applicable
only to samples when all the carbon is in the so-called combined
condition.

2. Solution in Chloride of Copper and Chloride of Potassium,
Filtration, and Combustion of the Residue in Oxygen.

As a solvent this salt has no advantage over the ammonium
salt, but the presence of carbonaceous matter in the latter, which
can only be removed by repeated crystallizations, has brought the
potassium salt into use. Solution is almost, if not quite, as rapid Advantages

. of the po-

with the potassium salt as with the ammonium salt, and the price
is decidedly in favor of the former. The absence of volatile con-
stituents is another advantage, for it is quite possible that chlo-
ride of ammonium if left in the carbonaceous residue may be
decomposed in the red-hot oxide of copper and form some com-
pound capable of being absorbed by the caustic potassa in the
Liebig bulb of the absorption apparatus. The only satisfactory

* See page 27. f Amer. Chem. Jour., iii. 245.

:62 ANALYSIS OF IRON AND STEEL.

way to test a solution of double chloride is to make several deter-
minations on a standard steel with each fresh lot of the solvent.

3. Solution in Chloride of Copper, and Combustion of the

Residue.

The only disadvantage in the use of this reagent is the
length of time required to dissolve a sample of steel in it. Even
with a strongly acid solution and constant stirring, unless the
sample is very finely divided, it may require several days for its
complete solution.

4. Solution in Iodine or Bromine, and Combustion with

Chromate of Lead, or "Weighing, of the Residue.

The determination by this method, when iodine is used, is
carried out exactly as directed for the estimation of " Slag and
Oxides," page 79, the residue being filtered on asbestos, dried,
and burned with chromate of lead or oxide of copper, as directed
Weighing in A. 2, page 132 et seq. The residue may also be filtered on
dueeresi a counterpoised filter* or Gooch crucible, washed, dried at 100°
C, weighed, the carbonaceous matter burned off, and the resi-
due weighed. The difference between the weights is the amount
of carbonaceous matter, which contains, according to Eggertz,f
59 per cent, of carbon. It also contains about 16 per cent, of
iodine, so that the residue cannot be burned in a current of
oxygen, nor with CrO3 and H2SO4. If bromine is used instead
of iodine, great care must be taken in adding the bromine, 10
c.c. bromine for 5 grammes of iron or steel, as the action is
very violent, and unless the bromine is added very slowly and
the solution kept as near o° C. as possible, there will be oxida-
tion, and, consequently, loss of carbon. The details of the
method when bromine is used are otherwise the same as when
iodine is the solvent.

* See page 27.

f Percy, Iron and Steel, page 891.

DETERMINATION OF TOTAL CARBON.

5. Solution by Fused Chloride of Silver, and Combustion of

the Residue.

Fuse in a porcelain crucible 20 grammes of chloride of silver, Details
and see that the button when cold has a smooth, flat surface on method,
top. Place the button in a porcelain dish about 6 inches ( 1 5 cm.)
in diameter, and pour on the button 3 grammes of drillings. Add
300 c.c. cold distilled water containing 2 drops of HC1, place the
dish on a ground-glass plate, and cover it with a bell-glass to
exclude the air during the time occupied in dissolving the sample.
It is not necessary that the sample should be in drillings, as a
single piece will be dissolved in this way. The chloride of silver
should weigh at least 6 times as much as the sample of iron or
steel. The reaction is a simple substitution, Fe+ 2AgCl — FeQ2
-f- 2Ag, by galvanic action, but secondary reactions occur, including
the decomposition of water, both hydrogen and oxygen being
taken up by the carbon at the moment of its liberation. A slight
excess of oxygen over the amount necessary to form water with
the hydrogen is taken up and a little hydrogen is liberated.
There is a tendency, of course, for the ferrous chloride when
formed to oxidize, consequently the air must be excluded. The
decomposition requires several days, as many as ten if the sample
of steel or iron is in a single piece and not very thin. The
metallic silver is quite cohesive, and is readily separated from the
carbonaceous residue. When the action is finished, remove the
mass of silver, washing off any of the carbonaceous matter ad-
hering to it, add a little HC1 to dissolve any ferric oxide which
may have formed, filter off, and burn the carbonaceous matter by
one of the methods previously described.

6. Solution of the Iron in Sulphate of Copper, Filtration,

and Combustion of the Residue in a Boat in a Current
of Oxygen.

Weigh 3 grammes of steel into a No. 3 beaker, and add 150
c.c. of solution of sulphate of copper, made by dissolving 200

164

ANALYSIS OF IRON AND STEEL.

Prepara-
tion of
sulphate
of copper
solution.

grammes of the copper salt in water, adding a dilute solution of
caustic soda until a slight permanent precipitate appears, allowing
it to settle, filtering through asbestos, and diluting to I litre. For
pig-iron, spiegel, and ferro-manganese, use I gramme, and 50 c.c.
of sulphate of copper solution. Heat the solution gently, and stir
well until decomposition is complete. Filter in a glass filtering-
tube on asbestos, as described on page 157. Wash well with
water, transfer to a boat, as directed on page 158, dry, and burn
in a porcelain tube, as directed for A. I, page 131. The results
are apt to be a' little low, owing to the difficulty of thoroughly
oxidizing the mass of copper mixed with the carbonaceous
matter.*

Instead of filtering off the mass of copper, carbonaceous matter,
etc., decant the clear supernatant fluid through the filtering-tube,
wash several times by decantation, and then dissolve the copper
in double chloride of copper and ammonium, chloride of copper,
or ferric chloride. Filter, wash the residue with a little dilute
HC1, and then with cold water, transfer to a boat, and burn as
directed on page 142 et seq.

7. Solution of the Iron in Sulphate of Copper, and Oxida-
tion of the Residue by CrO3 + H2SO4,

Treat the sample with solution of sulphate of copper, as in
the method just described. Allow the precipitated copper and
carbonaceous matter to settle, pour off the clear supernatant
liquid, and transfer the residue to the flask A (Fig. 75, page 160)
by means of a platinum spatula and a fine jet of water. The
water used should not exceed 20 or 25 c.c.f The apparatus is
that sketched in Fig. 75, the only difference being that the tube

* See report of the U. S. Board appointed to test iron, steel, and other metals,
vol. i. p. 284.

f The borings may be treated with the sulphate of copper solution in the flask
A, and the clear liquid drawn off with a pipette. This will avoid the necessity for
transferring the residue.

DETERMINATION OF TOTAL CARBON.

i65

O contains merely a little strong H2SO4.
exactly as described on page 159.

Effect the combustion

FIG. 76.

Description
of the ap-
paratus.

8. Solution in Dilute HC1 by the Aid of an Electric Current,
and Combustion of the Residue.

The arrangement shown in Fig. 76 may be used in carry-
ing out the details of this method. It consists of a Nc. 3
Griffin's beaker, in which is a piece of platinum-foil, the wire
from which connects with the negative pole of the battery; a
small basket of very fine platinum gauze is supported from a
platinum wire, on one end of
which is a clamp connecting
with the positive pole of the
battery. The battery is usually
a single Bunsen or Grove ele-
ment, and the intensity of the
current should be regulated by
varying the distance between
the foil and the basket, or by
introducing resistance-coils in
the connections, so that no gas
is given off from the iron. Hy-
drogen, of course, is given off
abundantly from the surface of

the foil, and the iron dissolves in the acid as ferrous chloride.
Weigh into the basket from i to 5 grammes of the sample,
which should be in pieces and not in powder. Suspend the
basket from the wire, having previously connected the rest of Details
the apparatus and poured into the beaker a mixture of 200 c.c.
water and 50 c.c. HC1, and regulate the intensity of the cur-
rent as directed above. When solution is complete, remove the
foil from the liquid, wash the carbonaceous matter from the
basket with a jet of cold water, and determine the amount of
carbon by one of the methods previously given.

of the
method.

1 66 ANALYSIS OF IRON AND STEEL.

DETERMINATION OP GRAPHITIC CARBON.

Karsten gave the first information in regard to the existence
of graphite in pig-iron, and he suggested dissolving the sample
in HNO3 with the addition of a few drops of HC1, in HC1 alone,
or in dilute H2SO4, boiling the residue with caustic potassa, filter-
ing, washing again with HC1, and finally with water, and weighing
the residue as graphite. A very interesting comparison of the
results obtained by the use of different solvents is given by
Drown,* and many experiments seem to show that the amount of
graphite found varies with the different acids used to dissolve the
sample, and also with the variations of treatment when the same
Solution acid is used. The usual method is as follows : Treat I gramme
of pig-iron or 10 grammes of steel with an excess of HC1, i.i
sp. gr. When all the iron is dissolved, boil for a few minutes,
allow the graphite to settle, and decant the supernatant fluid on
an asbestos filter, using either the perforated boat, Fig. 66, or
the filtering-tube, Figs. 70 and 71. Wash several times with hot
water by decantation, then pour on the residue in the beaker 30
c.c. of a solution of caustic potassa, sp. gr. i.i, and, when the effer-
vescence ceases, heat the solution to boiling. Filter on the same
filter, transfer the graphite, etc., to the filter, wash with hot water
again, and finally with alcohol and ether. Burn the graphite by
one of the methods given under " Determination of Total Carbon,"
and from the weight of CO2 obtained calculate the percentage
Comparison of carbon existing as graphite. It frequently happens, when the
obtaTntd5 sample is a high steel, that the residue which remains after treat-
by dis- jng jt as above js black, and contains carbon, but it is not crystal-
solving

in HCI line in appearance, and bears no resemblance to graphite. The

and

HN03. same steel will dissolve completely in HNO3, and when filtered
will not leave a trace of carbon on the felt. Steels containing
graphite give appreciably less carbon when dissolved in HNO3
than when dissolved in HCI. The method giving probably the

* Trans. Inst. Min. Engineers, vol. iii. p. 42.

DETERMINATION OF COMBINED CARBON.

167

most accurate and certainly the most uniform results is as fol-
lows: Dissolve the weighed sample in HNO3, sp. gr. 1.2, using solution in
15 c.c. of acid to each gramme taken for analysis. Filter on the
perforated boat or on an ignited asbestos filter, in a glass tube,
transfer the residue to the filter, and wash thoroughly with hot
water. Treat the residue on the filter with hot caustic potassa
solution, i.i sp. gr. (as the Si is all oxidized to SiO2 there will be
no effervescence), wash thoroughly with hot water, then with a
little dilute HC1, and finally with hot water. Burn the carbon by
one of the methods previously mentioned and calculate the CO2
obtained to carbon, and call the result graphite*

DETERMINATION OP COMBINED CARBON.

Indirect Method-
Having determined the total carbon and the graphite, by
subtracting the latter from the former we obtain the amount of
carbon existing in the combined condition.

Direct Method.

This method was first introduced by Eggertz,f in 1862. It
is based on the fact that when steel containing carbon is dis-
solved in HNO3, 1.2 sp. gr., the carbon, which sometimes at first
separates out in flocks of a brownish color, is eventually dis-
solved, giving to the solution a depth of color directly propor-
tionate to the amount of combined carbon in the steel. To use
this in practice it is only necessary to determine accurately the
amount of combined carbon contained in a steel, by a combustion
method, and to compare the depth of color in a solution of this
standard with that of any unknown steel, in order to ascertain the Limitatioll
amount of carbon in the latter. There is, however, a limitatation « the use

of this

in the application of this method. Reference was made on page method.

* Shimer (Jour. Amer. Chem. Soc., vol. xvii. p. 873, has shown that carbide of
titanium is insoluble in dilute hydrochloric acid and that the nitric acid method is the
only accurate one for the determination of graphite.

f Jern-Kontorets Annaler, 1862, p. 54; 1874, p. 176; 1881, 301; Chem. News,
vii. p. 254; xliv. p. 173.

ANALYSIS OF IRON AND STEEL.

129 to the fact that combined carbon is now believed to exist in
two conditions in steel, or rather that under circumstances a por-
tion of the combined carbon changes its condition, and, from a
chemical point of view, while it is still combined carbon, in that it
is soluble in HNO3, it fails to impart so dark a color to its nitric
acid solution as it did in its original state. The circumstances
under which a change of this kind occurs are quite well known,
and are merely those occasioned by the mechanical treatment to
which steel is submitted, such as hammering, rolling, hardening,
tempering, etc.* It may be stated, then, as a general proposition,
that the standard steel for the color-test should be of the same kind
and in the same physical condition as the samples to be tested.

To obtain the best results samples should be taken from the
original ingots that have not been reheated, rolled, or hammered ;
Bessemer steel should be compared with Bessemer, crucible with
crucible, open hearth with open hearth ; the standard should con-
tain approximately the same amount of carbon as the samples to
be tested, and should have as nearly as possible the same chem-
ical composition. The only elements that seem to have any de-
cided effect on the color of the nitric acid solution are copper,
cobalt, and chromium.

Details Weigh out carefully .2 gramme of each sample, including the

method standard, into test-tubes 6 inches (150 mm.) long and ^ inch (16
mm.) in diameter. The test-tubes should be perfectly clean and
dry, and each one marked with the number of the sample on a
small gummed label near the top. A little wooden rack (Fig. 77)
is convenient for holding the test-tubes in the weighing-room, and
to avoid all chance of error the tube is not placed in the rack
until the sample has been weighed and is ready to be transferred.

* Two very interesting papers on this subject will be found in the Chem. News,
J. S. Parker, "On the Varying Condition of Carbon in Steel," xlii. p. 88; T. W.
Hogg, "On the Condition of Carbon in Steel," xlii. p. 130. In my own practice I
have seen one-third of the total carbon changed from the combined form to the
graphitic in a high carbon steel by heating and hammering the ingot.

DETERMINATION OF COMBINED CARBON. jfo

A little platinum or aluminium dish about \y2 inches (40 mm.)
in diameter, with a spout, and furnished with a counterpoise
(Fig. 44, page 36), is very convenient for holding the drillings,
which are brushed from
it into the test-tube with
a camel's-hair brush. A
very excellent form of
water-bath is shown in
Fig. 78. It may be pro-
vided with a constant level
arrangement, consisting of
a tubulated bottle, the height of the end b of the vertical tube a Description
fixing the level of the water in the bath. A is the bath, and bath!*6
B the rack. The top of the rack is of sheet-copper, perforated to
receive the test-tubes, the bottoms of which rest on the coarse

C
7

r ^

V
i

(T\

FIG 78.

copper gauze, which is joined to the top by the uprights C. The
top of the rack rests on a flange around the top of the bath.

Place the test-tubes in the rack B, and stand the rack in the
bath which contains cold water. Drop into each test-tube, from

ANALYSIS OF IRON AND STEEL.

Amount of
HNO8 to
be used.

Apparatus
for de-
livering
different
volumes
of HNO8.

FIG. 79.

a pipette, the proper amount of HNO3, sp. gr. 1.2. For steels
containing less than .3 per cent, carbon use 3 c.c. HNO3; from
•3 to .5 per cent, carbon, 4 c.c. ; from .5 to .8 per cent., 5 c.c. ;
from .8 to I per cent., 6 c.c. ; and over I per cent, 7 c.c. An
insufficient amount of acid gives the solution a slightly darker
tint than it should properly have.

The apparatus shown in Fig. 79 * is useful for the rapid addi-
tion of different measured quantities of nitric
acid to the samples.

It consists of a glass reservoir holding
750 c.c., communicating below with four bu-
rettes graduated to deliver various quantities
of acid up to 10 c.c. Each burette is fur-
nished with a loose-fitting glass cap. The
burettes are fitted with three-way glass stop-
cocks, so that a quarter of a revolution con-
nects them with the reservoir, and when the
proper amount of acid has run in, the stop-
cock is turned another quarter, which shuts
off the reservoir and completely empties the
burette, thus delivering the exact amount
of acid measured, into the test-tube contain-
ing the weighed sample of steel in which
carbon is to be determined.
As shown in the cut, each test-tube stands in a bottle of cold
water to prevent too violent action of the acid during solution.
The whole apparatus is mounted on a rotary stand, and, as used
at the laboratory of the Bethlehem Iron Company, is contained
in a small hood near the drill and balance described on page 16,
so that the operator, seated on a revolving stool, can add acid
to one sample of steel while the drillings of the next sample
are falling into the balance-pan.

* Communicated to the author.

DETERMINATION OF COMBINED CARBON. j^j

The apparatus, as here shown, is a modification by Mr. Albert
L. Colby, chemist of the Bethlehem Iron Company, of an appa-
ratus first designed by Mr. E. A. Uehling in 1884.

The HNO3 is made by adding its own volume of water to Proper
acid of the usual strength, 1.4 sp.gr. It should be absolutely Of HNOS.
free from chlorine or hydrochloric acid, as, according to Eggertz,
.0001 gramme Cl in a nitric acid solution of .1 gramme iron in
2.5 c.c. HNO3 gives a decided yellow color. The HNO3 should
be added slowly, to prevent violent action, and the drillings
should not be too fine, for the same reason. Place in the top
of each test-tube a small glass bulb * or a very small funnel, and
heat the water in the bath to boiling, and boil until all the
carbonaceous matter is dissolved, shaking the tubes from time
to time to prevent the formation of any little film of oxide. The
time required for solution is for low steels about twenty minutes,
and for high steels (over I per cent, carbon) forty-five minutes,
After entire solution of the carbonaceous matter, prolonged heat-
ing tends to make the color lighter ; therefore, as soon as the
absence of small bubbles and the disappearance of any brownish
flocculent matter show complete solution, remove the rack from
the bath and stand it in a dish of cold water. The dish should
be about the same size as the bath, so that the top will be
covered by the top of the rack, thus excluding the light from
the solutions, in which case the color will not fade for a long
time. Under all circumstances the solutions should be kept out
of the light, and especially out of direct sunlight, as much as
possible. If there should be necessarily, in the steels operated
on at one time, a wide range in carbon, the test-tubes should
be removed from the bath as fast as their respective contents
are dissolved and placed in cold water in a dark place. The
appearance of the drillings will often give an idea of the approxi-

* These bulbs are easily made by sealing one end of a glass tube in the blow-
pipe flame, heating it, blowing a bulb of the proper size, allowing it to cool, heating
it above the neck, and drawing it out as shown in Fig. 77.

1/2

ANAL YSIS OF IRON AND STEEL.

Comparing
the
colors.

Compari-
son-tubes.

wood's

modifica-

tions for

mate carbon contents of a sample, but when there is no clue
whatever, it is best to begin by adding 3 c.c. HNO3 to the
weighed portion in the test-tube, and increase the amount
I c.c. at a time as the depth of color of the solution or
the amount of flocculent carbonaceous matter indicates
a higher carbon percentage. To compare the colors of
the solutions, pour the standard into one of the carbon
tubes (Fig. 80), wash out the test-tube with a little cold
water, add it to the solution in the carbon tube, and
dilute to a convenient amount.

This dilution should be sufficient to make the volume
of the diluted standard at least twice as great as the
volume of acid originally used to dissolve the sample, as
this amount of water is necessary to destroy the color
due to the nitrate of iron. It should not, however, greatly
exceed this amount, and should be in some convenient
multiple of the carbon contents of the standard in tenths
of a per cent. Thus, if a standard contains .45 per cent.
carbon, dilute the solution in the carbon tube to 9 c.c..
then each c.c. will equal .05 per cent. The carbon tubes
should be about ]/2 inch (12 mm.) in diameter, holding at
least 30 c.c., and graduated to ^ c.c. The tubes should
have exactly the same diameter, and the glass should be
perfectly colorless and have walls of the same thickness. They
should, of course, be most accurately graduated.

Mr. E. F. Wood,* of the Homestead Works, leaves the

...

lower ends of the tubes free from graduations to give a clear
space for comparing the colors. He considers this especially
necessary in low steels, for which he uses I gramme of the
sample, dissolves in 25 c.c. of nitric acid, boils for five to seven
minutes in a glycerine bath at 140° C, and compares in tubes
Y± inch (18 mm.) in diameter.

FIG. 80.

121

Communicated to the author.

DETERMINATION OF COMBINED CARBON.

173

The standard having been prepared, pour the solution of the
sample to be tested into another carbon tube, rinse the test-
tube into it with a little cold water, and compare the colors.
If the solution of the sample is darker than that of the stand-
ard, add water little by little, shaking the tube well to mix the
solution until the shades are exactly the same. Allow a minute
or two for the solution to run down the walls of the tube, and
read the volume. If the standard was diluted as above, then,
of course, each c.c. will equal .05 per cent, carbon, and if the
volume of the sample is 10.5 c.c. it will contain .525 per cent,
carbon. If the solution of the sample when first transferred to
the tube should be lighter in color than the standard, a lower
standard must be used, or this one may be diluted to, say, 13.5
c.c., in which case the number of c.c. divided by 3 will give
the percentage of carbon in tenths. The color may be com-
pared by holding the two tubes in front of a piece of white
paper held towards the light, but a camera made of light wood
and blackened inside is most convenient, and at night is quite
invaluable. It is shown in Fig.
8 1, and consists of a box 3^
inches (90 mm.) high inside, i^
inches (38 mm.) wide at one end,
and 5 inches (127 mm.) at the
other. It is 24 inches (610 mm.)
long, and is supported on a rod,
which can be raised and lowered
to suit the convenience of the ob-
server. The small end is closed
by a piece of ground-glass, which
slides in through a slot on top
I inch (25 mm.) from the end.
Immediately beyond this is an-
other slot to receive a thin piece of faintly blue glass, which is
inserted when the tests are made at night, using an oil-lamp

FIG. 81.

Description
of camera.

1y ^ ANALYSIS OF IRON AND STEEL.

placed on a stand just beyond the camera. In fact, in many
steel-works, to avoid the differences between the colors as seen
by daylight and lamplight, all comparisons are made in a dark
room, using a box or camera and an oil-lamp. Two holes in
the top of the camera just inside the ground-glass screen receive
the carbon tubes, the ends of which rest on a piece of black
cloth on the bottom of the camera inside. Another piece of
black cloth fastened across the top of the camera, covering
the top of the ground-glass slide, and having holes just large
enough to admit the tubes, excludes all light except that at the
back of the tubes. A north light is much the best for com-
paring the colors, and, as to most observers the left-hand tube
appears a little the darker, the color will be exactly matched
when, the tubes being reversed, the left-hand tube still appears a
little the darker of the two.

Use of per- Instead of diluting the solutions to agree with a standard, as

^ndards. above described, some chemists use a rack of permanent stand-
ards, as suggested by Britton.* The principal difficulty hereto-
fore attending the use of permanent standards has been the im-
possibility of preventing their fading ; but, according to Eggertz,f
this is now entirely overcome by the method of preparing them
suggested by Prof. F. L. Ekman. The details are as follows : Dis-
solve 3 grammes of neutral ferric chloride in 100 c.c. water con-
taining 1.5 c.c. HC1; dissolve 2.1 grammes cupric chloride in 100
c.c. water containing .5 c.c. HC1 ; dissolve 2.1 grammes cobaltic
chloride in 100 c.c. water containing 5 c.c. HC1, using the neutral

Preparation salts in all cases. These solutions will contain about .01 gramme
solution, of the metal to the c.c., and by adding to 8 c.c. of the iron solu-
tion 6 c.c. of the cobalt solution, 3 c.c. of the copper solution,
and 5 c.c. water containing .5 per cent HC1, a liquid is obtained
which has a color approximating to that obtained by dissolving
.2 gramme of steel, containing I per cent, of carbon, in HNO3, and

* Chem. News, xxii. 101. f Chem. News, xliv. 173.

DETERMINATION OF COMBINED CARBON. ij$

diluting to 10 c.c., or .1 per cent, carbon to the c.c. Prepare a

number of test-tubes of the size described on page 168, but in

this case it is essential that they should be of exactly the same

diameter, and that the glass should be as nearly colorless as pos-

sible. By successive dilutions with water containing .5 per cent. Preparation

HC1, of the normal solution prepared as above, make solutions of standards.

about the proper strength for the series required.

The variations should be about .02 per cent, between the differ-
ent tubes of the series, corresponding to, say, the even hundredths.
There should be about 10 c.c. of solution in each tube, and then
the color of each should be compared with a standard steel,
diluted to the exact strength required in the permanent standard.
For example, if the standard steel contains .4 per cent, carbon, and
you wish to get the exact color for the .32 per cent, carbon tube
in the permanent series, then dissolve .2 gramme of the standard
exactly as directed on page 170, pour the solution into a carbon
tube, and dilute it in accordance with the formula, carbon required
: carbon of standard : : 10 c.c. : the number of c.c. required, or, in
this case, 32 : 40 : : 10 c.c. : 12.5 c.c. Therefore dilute the solu-
tion in the carbon tube to 12.5 c.c., pour 10 c.c. into a test-tube
exactly like those used for the permanent standards, and compare
it with the .32 per cent, carbon tube. If the color of the perma-
nent solution is not exactly the same, correct it by adding por-
tions of the solutions of the iron, cobalt, or copper salts, or water
containing .5 per cent. HC1. The iron salt or HC1 alone gives a
yellowish, the cobalt salt a brownish, and the copper salt a green-

FIG. 82.

ish, tone to the solution. The standards may now be arranged in
a rack, as shown in Fig. 82. The colors of the permanent stand-
ards once fixed, the samples to be analyzed are treated exactly

ANALYSIS OF IRON AND STEEL.

Details of
method
when
using per-
manent
standards.

White cast
iron.

Filtering
from
graphite,
etc.

Stead's
method.

as described on page 170, the test-tubes used being precisely like
those containing the permanent standards, and each one carefully
graduated to contain 10 c.c. When the samples (.2 gramme each)
are dissolved and cooled, dilute each solution in turn with cold
water to 10 c.c., mix thoroughly, and compare it with the stand-
ards in the rack, by which means the carbon may be estimated to
the nearest hundredth of a per cent.

In testing white cast iron, use only .05 gramme, dissolve in 7
c.c. HNO3, dilute the standard to some convenient amount approxi-
mating 20 c.c., and compare as quickly as possible to avoid the
precipitation of carbonaceous matter, which is apt to occur under
these circumstances. The graphite in ordinary gray pig-iron, and
sometimes even in steels, renders filtration necessary. In this case
add to the cold acid solution one-half of its volume of water, filter
through a small, dry, ashless filter into the carbon tube, wash with
as little water as possible, and compare as usual.

For steels very low in carbon, the color test, as above described,
becomes uncertain, but Stead* has suggested and elaborated a
method which gives excellent results. It is based on the fact that
the carbonaceous matter liberated from iron and steel is soluble in
the caustic alkalies as well as in HNO3, while the color which it
imparts to the alkaline solution is about 2^ times as great as that
which it gives to the acid solution. For this method is required,
besides the HNO3, 1.2 sp. gr., a solution of caustic soda 1.27 sp. gr.
Weigh I gramme of each sample, including the standard, into a
No. I beaker, add 12 c.c. HNOS, and heat on the bath until solution
is complete, which, in the case of puddled iron or low steel, is in
about five or ten minutes. Add to each 30 c.c. of boiling water
and 13 c.c. of the soda solution, stirring well. Pour each solution
in turn into a glass measuring-jar, dilute to 60 c.c., mix thor-
oughly, allow the solution to settle, filter through a dry filter, and
receive 15 c.c. of each sample in a carbon tube. Those samples

* Jour. Iron and Steel Institute, 1883, No. I, p. 213.

DETERMINATION OF COMBINED CARBON.

177

whose solutions are darker than that of the standard contain, of
course, more carbon than the standard. Dilute the solutions in
turn until the colors agree with that of the standard. The per-
centage of carbon is deduced from the equation — x^=^, in

which a is the percentage of carbon in the standard, 15, of course,
the number of c.c. taken of each solution, b is the number of c.c.
in the diluted sample, and x is the percentage of carbon in the
sample. Take those samples whose solutions are lighter than
that of the standard, and dilute the standard until its color is the
same as that of the darkest of
the samples, read the volume,
and dilute it for the next darkest,
and so on through the series.
The percentage of carbon in
each sample is then deduced

FIG. 83.

a
from the equation -, X 1 5 =

ITs

the letters having the meaning

given above. They may also

be compared by pouring into

measuring-tubes until the colors

appear equal when looked at

from above. The carbon in

this case is inversely as the

length of the column. To facili-

tate the comparison, Stead (loc.

cit.) has devised a very simple

instrument based on this last

principle. It consists (Fig. 83)

of two parallel tubes of any con-

venient diameter fastened to a

frame. The tube b is open at both ends, but is contracted at

the point c. The contracted end passes through the stopper of

=L19

i.18
1L17
I.16

Tl5

ANALYSIS OF IRON AND STEEL.

the bottle d, and reaches almost to the bottom of the bottle. A
small tube, et which ends just below the stopper, is connected
with a bulb syringe, f. The tube a is closed at the lower end,
and contains a small, solid, glazed china cylinder, which rests
on the bottom. A similar cylinder rests just above the con-
traction in the tube b, and the tubes are so arranged that the
upper flat surfaces of the cylinders are on the same level, and
exactly the same distance from the open tops of the tubes. The
scale g is graduated in .02 up to .20 from the level of the upper
surfaces of the cylinders to a point marked on the tube a, 10
inches (254 mm.) above. A solution of a standard steel contain-
ing .2 per cent, carbon, prepared as above, is placed in the bottle
d, and a similar solution of a sample to be tested is poured into
the tube a up to the mark. By squeezing the bulb f a column
of the standard solution is forced up the tube b, and when, by
looking into the mirror, placed at an angle of 45°, the color in the
two columns appears equal in intensity, the percentage of carbon
is read off on the scale opposite the top of the column in b. The
alkaline solution is said to keep its color unaltered for a month
when not exposed to direct sunlight.

DETERMINATION OF TITANIUM.

By Precipitation.

Only traces or very minute amounts of titanium are found
in steel, but notable quantities exist in some kinds of pig-iron.
As pointed out by Riley,* when pig-iron containing titanium is
dissolved in HC1 a portion of the titanium goes into solution,
while the remainder is found with the insoluble matter. The
insoluble portion, as noticed on page 86 et seq., contains P2O5.
It is a curious fact that while TiO2 interferes with the deter-

* Jour. Chem. Soc., xvi. 387.

DETERMINATION OF TITANIUM.

mination of P2O5 by its tendency to form upon evaporation to insoluble

phospho-

dryness an insoluble phospho-titanate, so P2O5 interferes with

the determination of TiO2 by partially preventing the precipita-

tion of TiO2 from its boiling sulphuric acid solution. The best Separation

method- therefore, for the determination of titanium is to proceed

exactly as for the determination of phosphorus when titanium

is present, as directed on page 86 et seq., until the residue from

the aqueous solution of the carbonate of sodium fusion is ob-

tained. Dry this residue, transfer it to a large platinum crucible,

preferably the one in which the carbonate of sodium fusion was

made, burn the filter, add its ash to the residue, and fuse the

whole with 15 or 20 times its weight of bisulphate of potassium.

In fusing with bisulphate of potassium it is necessary to begin Fusion

with a very low heat, and to raise the temperature very slowly KHSO*

and carefully to a low red heat, as the mixture has a strong

tendency to boil over the top of the crucible whenever the tem-

perature is increased too rapidly. When the lid of the crucible

is raised, fumes of SO3 should come orT, and the fusion should

be kept at this point for several hours, or until it is quite clear

and the whole of the ferric oxide has been dissolved. Incline

the crucible as far as possible on one side while the fused mass

is still liquid, and allow it to cool in this position. The mass

will harden in a cake on the side of the crucible, and can be

readily detached without bending the sides of the crucible. Place

the crucible and lid in a No. 4 beaker, and suspend in the

beaker a little platinum wire-gauze basket containing the fused

mass, as shown in Fig. 76, page 165. Pour into the beaker 50

c.c. of strong sulphurous acid water, and fill the beaker to the

top of the fused mass in the basket with cold water. Under Solution of

the bisul-

these circumstances the fused mass dissolves quite rapidly, as
the concentrated solution falls to the bottom, and the iron is at
the same time deoxidized. Without the basket, it is necessary
to stir the liquid constantly, and the time occupied in dis-
solving the fused mass is much prolonged. When solution is

ANALYSIS OF IRON AND STEEL.

complete, remove the basket, the crucible, and the lid from the
beaker, wash them with a jet of cold water, and filter the solu-
tion into a No. 5 beaker. Add a filtered solution of 20 grammes
acetate of sodium and one-sixth the volume of the solution of
acetic acid, 1.04 sp. gr., to the filtered solution, and heat to
boiling. The titanic acid is precipitated almost immediately in a
flocculent condition, and quite free from iron. Boil for a few
minutes, allow the titanic acid to settle, filter, wash with hot
water containing a little acetic acid, dry, ignite, and weigh as
TiO2, which contains 60.00 per cent. Ti. Instead of fusing the
residue from the aqueous solution of the carbonate of sodium
fusion with bisulphate of potassium, the operation may be hast-
ened as follows :

Treatment Transfer the residue to the large crucible, as before directed,

th and fuse with 5 grammes of dry carbonate of sodium. Allow

H2so4. tke crucify f-0 cool, ancj then pour into it very gradually strong
H2SO4. When the effervescence slackens, warm the crucible
slightly, and continue the addition of H2SO4 and the careful
application of heat until the fusion becomes liquid and the ferric
oxide is all dissolved. Heat carefully until copious fumes of
SO3 are given off, allow the crucible to cool, and pour the con-
tents, which should be just fluid when cold, into a beaker con-
taining about 250 c.c. of cold water. Add to it 50 c.c. of a
strong aqueous solution of sulphurous acid, or 2 or 3 c.c. of
bisulphite of ammonium, filter if necessary, nearly neutralize by
NH4HO, allow it to stand until it is entirely decolorized, add 20
grammes acetate of sodium and one-sixth its volume of acetic
acid, 1.04 sp. gr., and precipitate the TiO2 as before.

By Volatilization.

Drown* suggested the method of determining titanium by
volatilizing it in a current of chlorine gas. The details, with

* Trans. Inst. Min. Engineers, viii. 508.

DETERMINATION OF COPPER.

some modifications, are as follows. Treat the sample exactly as
directed for the determination of silicon, by volatilization in a
current of chlorine gas, page 73 et seq.

To the filtrate from the silica, page 76, add a slight excess
of NH4HO, acidulate with acetic acid, boil, filter, wash, and
ignite the precipitate. As this precipitate may contain a little
ferric oxide (carried over mechanically as Fe2Cl6), phosphoric
acid, tungstic acid, etc., fuse it with a little carbonate of sodium,
dissolve the fused mass in hot water, filter, wash, dry, and ignite
the residue, which will contain all the titanic acid as titanate of
sodium, and any iron that may have been present as Fe2O3.
The filtrate will contain the P2O5, etc. Fuse the ignited residue
with a little carbonate of sodium, treat it in the crucible with
strong H2SO4, as directed on page 180, and determine the TiO2
in the manner there described.

DETERMINATION OF COPPER.

For the determination of copper the precipitate by H2S, ob-
tained in the determination of phosphorus, page 84, may be used,
but in this case the precipitate must be filtered off before getting
rid of the excess of H2S, after which, if any additional precipi-
tate of As2S3 is thrown down in the filtrate, it must be filtered off
before proceeding with the determination of phosphorus. Dry
and ignite the filter with the precipitate of CuS, etc., in a porce-
lain crucible, burn off all the carbon from the paper, allow the
crucible to cool, and digest the precipitate at a gentle heat with
HNO3 and a few drops of H2SO4, keeping the crucible covered
with a small watch-glass. When the CuS is entirely dissolved,
remove the watch-glass and evaporate the solution until all the
HNO3 is expelled and fumes of SO3 are given off. Allow it to
cool, add enough water to dissolve all the CuSO4, heating gently,

182

ANALYSIS OF IRON AND STEEL.

if necessary, and wash the solution into a platinum crucible.
- Place the crucible in the little brass holder (Fig. 84), and attach
eiectroiy- the weighed platinum cylinder and connect the battery. The
battery should consist of three Daniell's 2-quart cells, arranged
as shown in Fig. 85. The connectors a, b pass through the sides
of the box (which should be kept covered), and, the jars being

FIG. 84.

connected as shown in the sketch, by simply changing the wire
from a to b, three cells are brought into action instead of two.
For depositing the small amount of copper found in iron or steel,
two cells furnish a sufficiently strong current. The platinum cyl-
inder should weigh about 3 or 4 grammes; it is lowered into
the liquid until it is just clear of the bottom of the crucible, and
the crucible is covered with two small pieces of glass to prevent
liquid being carried off by the escaping gas. It is much neater
to deposit the copper on the cylinder than in the crucible, as it
weighs less, is quite as easy to wash and dry, and there is no
danger of any silica or dirt from the solution being covered by
the deposited copper. When the copper is all deposited, usu-
ally in two or three hours, remove the cylinder, wash it with
cold water, then with alcohol, dry at 100° C, cool, and weigh.
The increase of weight is Cu.

DETERMINATION OF COPPER. ^

In pig-irons containing titanium it is necessary to use a Using solu-
tion from
separate portion for the determination of copper. In steels, the s, deter-

solution in the flask from the determination of sulphur (page 61) ™stedsn
may be used for the determination of copper. In this case, wash
the contents of the flask into a No. 5 beaker, nearly neutralize
with NH4HO, add 5 c.c. HC1, heat the solution to boiling, and
pass H2S through the boiling solution for fifteen or twenty min-
utes, filter, wash with hot water, and treat the precipitate as
directed above. In the case of pig-irons, however, it is best to Procedure
dissolve in aqua regia, evaporate to dryness, redissolve in HC1, iron.
filter, reduce the iron in the filtrate with NH4HSO3, boil off the
excess of SO2, and precipitate by H2S. Instead of using H2S,
the copper may be precipitated in a sulphuric acid solution by
hyposulphite of sodium. Dissolve 5 grammes of the sample in Predpita-

tion by

a mixture of 150 c.c. H2O and 12 c.c. strong H2SO4. Dilute

to about 500 c.c. with hot water, heat to boiling, and add 3
grammes of hyposulphite of sodium dissolved in 10 c.c. hot
water. Boil for a few minutes, allow the precipitate to settle,
and filter and wash with hot water. Dry the precipitate, which
besides the CuS will consist of the graphite, silica, etc. ; transfer
it to a small beaker, burn the filter, and add the ash to the main
portion. Digest the whole with aqua regia, dilute with hot
water, filter, wash, add a few drops of H2SO4, and evaporate
until fumes of SO3 are given ofT, cool, dissolve in water, transfer
to the platinum crucible, and determine the copper by the battery
as directed above.

Instead of determining the copper by electrolysis, it may be
determined as subsulphide, Cu2S, or as oxide, CuO. To deter- GUSS.
mine it as Cu2S, dilute the sulphate obtained by any of the
methods mentioned above with water to about 50 c.c., add an
excess of NH4HO, filter from Fe2O3, etc., wash with ammoniacal
water, and pass H2S through the cold solution. Filter, wash
with H2S water, dry the filter and precipitate, transfer the latter
to a small porcelain crucible, burn the filter, and add its ash to

tion as

1 84

Determina-
tion as
CuO.

ANALYSIS OF IRON AND STEEL.

the precipitate. Add to the precipitate in the crucible about
twice its volume of flowers of sulphur and ignite it in a current
of hydrogen, as directed for the determination of manganese
as MnS, page 114. Weigh as Cu2S, which contains 79.82 per
cent. Cu.

Instead of igniting the precipitate obtained above as Cu2S,
the copper may be determined as CuO, as follows : Dissolve the
sulphide in aqua regia in a small porcelain dish, evaporate nearly
dry, dilute with hot water, heat to boiling, and add a slight
excess of a dilute solution of caustic soda or potassa. Filter on
a small ashless filter, wash with hot water, dry, transfer the pre-
cipitate to a platinum crucible, burn the filter and add its ash
to the precipitate, moisten the whole with HNO3, and heat very
gently at first, but increase the heat slowly to redness. Cool,
and weigh as CuO, which contains 79.85 per cent. Cu.

Separation
from Cu.

DETERMINATION OF NICKEL AND COBALT.

Treat 3 grammes of the drillings exactly as directed for the
determination of manganese by the acetate method, page 103 et
seq. The precipitate by H2S, page 112, will contain all the nickel
and cobalt and a portion of the copper contained in the sample.
Filter this precipitate on a small washed filter, wash with H2S
water containing a little free acetic acid, dry and ignite the filter
and precipitate, and transfer them to a No. I beaker. Dissolve
in HC1 with a few drops of HNO3, evaporate to dryness, redis-
solve in 10-20 drops of HC1, dilute with hot water to about 50
c.c., heat the solution to boiling, and pass a stream of H2S
through the boiling solution to precipitate any copper that may
be present. Filter, wash with hot water, evaporate the filtrate to
dryness, moisten the dry mass with 4 or 5 drops of HC1, add 20
or 30 drops of cold water, and then 2 or 3 grammes of nitrite

DETERMINATION OF NICKEL AND COBALT. 185

of potassium (KNO2) * dissolved in the least possible amount of
water, and acidulated with acetic acid. The presence of cobalt separation
is shown by the formation of a bright yellow precipitate of the GO.
double nitrite of cobalt and potassium, (KNO2)6Co2(NO2)6 -f- Aq.
Stir the solution, and allow it to stand twenty-four hours, with
occasional stirring. Filter on a small ashless filter, wash with
water containing acetate of potassium and a little free acetic
acid, remove the filtrate which contains the nickel, and wash the
precipitate and filter free from acetate of potassium with alcohol.
Ignite the filter and precipitate carefully in a porcelain crucible,

. r . i • i r

being careful not to raise the temperature high enough to fuse

the precipitate; transfer to a very small beaker, and digest in

HCl and a little KClO3. Evaporate to dryness, redissolve in

3-5 drops of HCl, dilute with cold water, add about I gramme

of acetate of sodium, and boil for an hour to precipitate the

small amount of Fe2O3 and Al2O3 that is always present. Filter,

to the filtrate add excess of NH4HO and NH4HS, and heat to

boiling. As soon as the precipitate of CoS has settled, filter,

wash with water containing a little NH4HS, dry and ignite the

precipitate and filter, in a platinum crucible. When all the car-

bon is burned, allow the crucible to cool, pour in a little HNO3,

heat carefully, and finally evaporate to dryness. Add a few AsCoSO4.

drops of H2SO4, digest until the sulphide and oxide are changed

to sulphate of cobalt, drive off the excess of H2SO4, heat finally

to dull redness for a few moments, cool, and weigh as CoSO4,

which contains 38.05 per cent, of cobalt. Heat the filtrate from

the double nitrate of cobalt and potassium to boiling, add a

slight excess of caustic potassa, boil for a few minutes, filter,

and wash the precipitate of oxide of nickel with hot water. Dis-

solve the precipitate on the filter with HCl, allow the solution
to run back into the beaker in which the oxide of nickel was
precipitated, and wash the filter with hot water. Evaporate

See page 47.

1 86

ANALYSIS OF IRON AND STEEL.

As Ni2S or
NiO.

Determina-
tion by
electroly-
sis as Ni
+ Co.

Determina-
of Co.

Determina-

of Ni.

the solution to dryness, redissolve in 3-5 drops of HC1, dilute
with cold water to about 50 c.c., add about I gramme of ace-
tate of sodium, boil for about an hour, filter off any Fe2O3 and
A12O3, and wash with hot water. To the filtrate add an excess
of NH4HS (a brown color shows the presence of nickel), acid-
ulate with acetic acid, heat to boiling, and pass a current of
H2S through the boiling solution until the precipitated sulphur
and sulphide of nickel agglomerate. Filter, wash with H2S water,
dry and ignite the filter, and precipitate. Allow the crucible
to cool, add a little carbonate of ammonium to the precipitate,
heat to dull redness, and volatilize any sulphuric acid that may
have been formed as sulphate of ammonium, cool, and weigh as
Ni2S or NiO, which contains 78.55 per cent, of nickel. The
nickel and cobalt may also be weighed in the metallic condi-
tion by precipitating them by the battery from the ammoniacal
solutions of the sulphates. If it is not desired to separate them,
evaporate the filtrate from the precipitated sulphide of copper
with an excess of H2SO4 until the HC1 is driven off and fumes
of SO3 appear, allow the beaker to cool, add about 5 c.c. water,
then an excess of NH4HO, filter if necessary, transfer to a plat-
inum crucible, and precipitate on the small cylinder (Fig. 84,
page 176) in a strongly ammoniacal solution, using three cells of
the battery. Wash the cylinder with water, then with alcohol,
dry at 100° C, and weigh as Ni -f- Co. To determine the nickel
and cobalt separately, precipitate the cobalt as double nitrite of
cobalt and potassium, treat the ignited cobalt precipitate with
an excess of H2SO4, heat until fumes of SO3 are given off, di-
lute a little, make the solution strongly ammoniacal, and pre-
cipitate the cobalt as above directed. Precipitate the NiO, in
the filtrate from the cobalt, by KHO solution, filter, wash, dis-
solve on the filter in HC1, evaporate the solution with H2SO4,
add excess of NH4HO, and precipitate the Ni by the battery
as above.

For the analysis of nickel steel, which contains from 2 to 3 per

DETERMINATION OF CHROMIUM AND ALUMINIUM. 187

cent, of nickel, use I gramme of the sample, and, after obtaining Nickel steel,
the precipitate of NiS as described above, burn it with the filter in
a porcelain crucible, allow it to cool, add a little pure powdered
sulphur, and ignite in a stream of hydrogen gas as described on
page 114. Weigh as Ni2S.

DETERMINATION OF CHROMIUM AND ALU-
MINIUM.

Weigh 5 grammes of drillings into a flask of about 500 c.c.
capacity, and pour in 20 c.c. strong HC1 diluted with 3 or 4 times
its bulk of water. Close the flask with a rubber stopper carrying
a valve which is made as follows. Bore a hole through the centre Bunsen
of a rubber stopper, and insert a piece of glass tubing long enough
to extend from the small end of the stopper to a distance of I inch
(25 mm.) beyond the large end. Take a piece of heavy soft rubber
tubing 2 inches (50 mm.) long, and cut a longitudinal slit in the
middle about ^ inch (12 mm.) long. Close one end of the tube
with a piece of glass rod ^ inch (12 mm.) long, and fit the other
end over the glass tube in the stopper for a distance of J^ inch
(12 mm.). This valve allows the gas to escape from the flask, but
prevents air from entering it, so that the iron is not oxidized, but
remains dissolved as ferrous chloride. Heat the dilute acid in the
flask if necessary, and when the iron or steel is entirely dissolved
remove the stopper, drop a small piece of Na2CO3 into the flask,
and close it with a solid rubber stopper. Cool the flask with its
contents as quickly as possible, and dilute the solution with cold
water until the flask is three-fourths full. Add BaCO3,* shaking
constantly until the solution appears milky with the excess of
BaCO3. Loosen the stopper to allow the CO2 to escape, shake

* See page 50.

i88

ANALYSIS OF IRON AND STEEL.

Cr and Al
insoluble
in HC1.

Separation
of Cr and
Al from
Feby
NH4HS.

Separation
of Cr and
Alby
Dexter's
method.

the flask at intervals for several hours, and allow it to stand over-
night, the stopper being pushed well into the neck. The precipi-
tate will consist of all the A12O3, Cr2O3, Fe2O3 from the solution, as
well as P2O5, etc., and the graphite and silica that were insoluble in
the dilute acid ; it should be quite white from the excess of BaCO3
added. Filter as rapidly as possible, wash with cold water, dis-
solve on the filter in dilute HC1, allow the solution to run into a
small beaker, clean out the flask with the same acid, and wash it
and the filter well with hot water. The insoluble matter left on
the filter may contain some chromium and aluminium insoluble in
dilute HC1, and usually in the form of slag, or in puddled iron as
oxides. This may be ignited, treated with HF1 and H2SO4, evapo-
rated to dryness, fused with Na2CO3 and KNO3, and the Cr2O3 and
A12O3 determined, or the solution of the fused mass in dilute HC1
added to the filtrate from the insoluble matter. Boil this filtrate,
add a slight excess of H2SO4 to precipitate all the barium, allow
the precipitate of BaSO4 to settle, filter, and wash with hot water.
Evaporate the filtrate to get rid of the excess of acid, dilute with
cold water, add sufficient tartaric or citric acid to hold the iron in
solution, add an excess of NH4HO, and to the solution, which
should be perfectly clear, an excess of NH4HS. Allow the pre-
cipitated FeS to settle, filter, wash with water containing NH4HS,
evaporate the filtrate to dryness in a large platinum crucible, heat
to redness to volatilize the ammonium salts, and burn the carbon
formed from the decomposition of the tartaric acid. Fuse the
residue with 6 parts Na2CO3 and I part KNO3, dissolve out in
water,* transfer to a beaker, add 2 or 3 grammes KC1O3, rinse out
the crucible with HC1, add it to the solution, and then add a slight
excess of HC1. Evaporate to syrupy consistency on the water-
bath, adding a little KC1O3 from time to time to decompose the
excess of HCl.f Redissolve in water, add an excess of carbonate

* If the fusion or its concentrated aqueous solution is not yellowish in color
there is no chromium present.

f Dexter, Pogg. Annal., 89, 142.

DETERMINATION OF CHROMIUM AND ALUMINIUM.

of ammonium to precipitate the A12O3, and boil off all smell of
ammonia. The alumina will be precipitated as phosphate, wholly
or in part, if the sample contains phosphorus, while the chromium
is in solution as chromate of potassium or sodium. Filter, wash
with hot water, reserve the filtrate and washings, redissolve the
precipitate on the filter in HC1, allowing the solution to run into
a small beaker, evaporate to dryness to render any silica insoluble,
redissolve in HC1, filter, to the filtrate add excess of NH4HO and
NH4HS, boil, filter on a small ashless filter, wash with hot water,
ignite, and weigh as A12O3, which contains 53.01 per cent. Al.
Acidulate the solution containing the chromium with HC1, heat to
decompose the excess of KC1O3, add a little alcohol, and evaporate
to dryness to render silica insoluble. The chromium is now in Determina-
the condition of Cr2O3; redissolve in HC1, dilute, filter off any
silica that may be present, to the filtrate add an excess of NH4HO,
boil, filter on a small ashless filter, wash well with hot water, ignite,
and weigh as Cr2O3, which contains 68.48 per cent, of chromium.
As the precipitates of A12O3 and Cr2O3 may both contain P2O5, it is
necessary to fuse each of them, after weighing, with a little Na2CO3,
dissolve in water, filter, acidulate with HNO3, and determine the
P2O5 by the molybdate method, or acidulate with HC1* add a little separation
citric acid and magnesium mixture, and determine the P2O5 as
Mg2P2O7. Calculate the amount of P2O5, subtract its weight from
that of the A12O3 and Cr2O3 respectively, and calculate the re-
mainder to Al and Cr, as directed above.

Instead of separating the aluminium and chromium by HC1
and KC1O3, as directed above, the better method suggested by
Genth * may be used, which is as follows : Dissolve in water
the fusion of the residue from the volatilization of the ammonium
salts and the decomposition of the tartaric acid, transfer it to a
platinum dish, add a few grammes of nitrate of ammonium, and
evaporate down on a water-bath until the solution is syrupy,

* Chem. News, vi. 32.

ANALYSIS OF IRON AND STEEL.

adding NH4NO3 from time to time until the addition fails to
produce any further evolution of NH4HO from the solution.
Add a little carbonate of ammonium towards the end of the
operation, and when the solution is syrupy and smells very
faintly of ammonia, dilute and filter from the A12O3, which treat
as directed above. To the filtrate add a strong aqueous solution
of sulphurous acid, boil off the excess of SO2, and add NH4HO
to alkaline reaction. Boil, filter, wash, ignite, and weigh the
Cr2O3, which must be tested for P2O5 as above directed. To
a- determine chromium alone in iron or steel, treat 5 grammes with
alone. HC1, precipitate by BaCO3, filter, and wash the insoluble matter
and precipitate, as directed above. Place a clean beaker under
the funnel, pierce the filter, and wash the contents into the
beaker. Clean the flask and filter with hot dilute HC1, and
wash them thoroughly with hot water, allowing all the acid and
washings to run into the beaker. Add enough HC1 to dissolve
the soluble part of the precipitate (Fe2O3, Cr2O3, A12O3, BaCO3),
dilute, boil, and precipitate the Cr2O3, etc., with NH4HO. Boil
off all smell of ammonia, allow the precipitate to settle, and wash
well with hot water. Dry, and transfer the precipitate to a platinum
crucible, carefully separating it from the filter, ignite the filter, and
add its ashes to the precipitate in the crucible. Before heating
the precipitate, add to it in the crucible 3-6 grammes Na2CO3
and y2 gramme KNO3 (with pig-irons it is necessary to add 2-3
grammes KNO3 to oxidize the graphite), and mix thoroughly.
Heat gradually to fusion, and finally raise the heat until all the
KNO3 is decomposed. Cool, treat the fused mass with hot water,
filter from Fe2O3, wash well with hot water, acidulate the filtrate
with HC1, and evaporate to dryness with a little alcohol. Redis-
solve in HC1, dilute, filter from SiO2, and in the filtrate precipitate
the Cr2O3 by NH4HO. Filter, wash thoroughly, dry, ignite, and
weigh as Cr2O3. This precipitate may contain also some A12O3
and P2O5, which must be separated in very accurate determina-
tions, and the amounts subtracted from the first weight of Cr2O3.

DETERMINATION OF CHROMIUM AND ALUMINIUM. IQI

Determination of Aluminium, Stead's Method.*
Weigh off 6-12 or 24 grammes steel, place in 600 c.c. beaker,
cover with watch-glass, dissolve it in HC1 (strong), evaporate to
dryness, redissolve in HC1, filter into 1000 c.c. beaker through
an ashless filter, wash filter containing silica, nearly neutralize
the filtrate with dilute ammonia, and boil filtrate, which should
measure about 500 to 600 c.c. Add to the solution I or 2 c.c.
of saturated solution of ammonium phosphate, and then a large
excess of sodium hyposulphite, boil till all SO2 has passed off
(half an hour's boiling should be sufficient) ; just before filtering
add 20 c.c. of a saturated solution of ammonium acetate, stir to
mix, and filter through an ashless filter, wash precipitate and
filter 5 or 6 times, add to the beaker from which the solution
and precipitate had been formed 10 c.c. HC1, heat to boiling, re-
move the vessel containing the filtrate, and place instead of it
under the funnel a platinum dish, and pour over the filter the
boiling acid. Rinse out the beaker and wash all soluble mat-
ter on the filter with a fine jet, evaporate the solution to dry-
ness in the platinum dish, and heat, to drive off excess of acid, on
the sand-bath to a temperature of 300° or 400° F.

Add from 2 to 5 grammes pure sodium hydrate made from
sodium free from alumina and about 2 c.c. water. Heat gently
over a rose-burner for ten minutes, maintaining the mass in a
fluid state all the time. Cool and add water, and boil till solu-
tion is complete. Make the bulk of the solution to 300 c.c. and
note the temperature exactly. Shake well and filter through an
ashless filter. Measure off 250 c.c. at the original temperature,
equal to 5-10 or 20 grammes steel. If any yellow tint is ob- indication
servable chromium may be present. In such a case the phos- mium.
phate of alumina must be neutralized with HC1 and precipitated
by ammonium carbonate, taking care to boil the solution well
to free from excess of ammonia before filtering. Filter off

* Prepared by Mr. J. E. Stead, of Middlesboro', England, for this volume.

ANALYSIS OF IRON AND STEEL.

through an ashless filter, dry, burn off, and weigh, dissolve pre-
cipitate in HC1 and determine P2O5 in it, and deduct the weight
found from the weight of the original precipitate. If chromium
is absent, neutralize the solution with HC1 as before described,
boil and add excess of sodium hyposulphite, and boil for half
an hour, filter off precipitate, burn, and weigh as pure aluminium
phosphate, which contains 22.18 per cent, of aluminium.

Carnot's Method.*

M. Carnot states that the method is very similar to that pub-
lished by Mr. J. E. Stead in the Journal of the Society of Chem-
ical Industry, 1889, page 965, but that he has used and taught
it at the Ecole des Mines for eight years. It is founded on the
reaction that he pointed out in 1881, that aluminium is precipi-
tated as the neutral phosphate from a boiling solution faintly
acid with acetic acid. The precipitation succeeds equally well
when the solution contains iron, if the ferric salt has been pre-
viously reduced to ferrous by hyposulphite of soda.

Treat 10 grammes of the iron or steel in a platinum dish
covered with a piece of platinum-foil with hydrochloric acid,
and when solution is complete, dilute and filter into a flask,
washing the carbon, silica, etc., on the filter thoroughly with
distilled water. Neutralize the solution with ammonia and car-
bonate of soda, but see that no permanent precipitate is formed,
then add a little hyposulphite of soda, and, when the liquid at
first violet becomes colorless, 2 or 3 c.c. of a saturated solution
of phosphate of soda and 5 or 6 grammes of acetate of soda dis-
solved in a little water. Boil the solution about three-quarters of
an hour, or until it no longer smells of sulphurous acid. Filter,
and wash the precipitate of phosphate of alumina, mixed with a
little silica and ferric phosphate, with boiling water. Treat the
precipitate on the filter with hot dilute hydrochloric acid, allow
the solution to run into a platinum dish, evaporate to dryness,

* A. Carnot, Moniteur Scientifique, 1891, p. 14.

DETERMINATION OF CHROMIUM AND ALUMINIUM. 193

and heat at 100° for an hour to render the silica insoluble. Dis-
solve in hot dilute hydrochloric acid, filter from the silica, dilute
to about IOO c.c. with cold water, neutralize as before, add a
little hyposulphite in the cold, then a mixture of 2 grammes of
hyposulphite and 2 grammes of acetate of soda, wash, and weigh
as A1PO4, which contains 22.18 per cent, of aluminium.

Determination of Chromium. Volumetric Method for
Chromium.

Galbraith * has suggested a rapid method for the determina-
tion of chromium when it is present in appreciable amounts, as
in chrome steel or chrome pig-iron. Dissolve 1-3 grammes of
the sample in dilute H2SO4 (i part H2SO4 and 6 parts water),
add permanganate of potassium in crystals until the iron is all
oxidized and the liquid is quite red in color, then add as much
more to oxidize the chromium to CrO3. Heat the solution to
boiling, and boil until the permanganate is all decomposed and
there remains a precipitate of oxide of manganese. Filter, wash
with hot water, to the filtrate add a measured volume of stand-
ardized ferrous sulphate, and determine the excess of ferrous
sulphate by a standard solution of permanganate. From the
amount of ferrous sulphate oxidized by the CrO3 calculate the
amount of Cr. The reaction is 6FeSO4+ 2CrO3 + 6H2SO4 =
3Fe2(SO4)3 -f Cr2(SO4)3 + 6H2O, or I equivalent of chromic acid
will oxidize 3 equivalents of ferrous sulphate to ferric sulphate.
Therefore, if the value of the permanganate is known in metal-
lic iron, and consequently the value of the ferrous sulphate (it
being standardized by the permanganate) in metallic iron, the
amount of chromium is calculated as follows: 3 equiv. Fe=
1 68 : I equiv. Cr= 52.14 :: the value of the ferrous sulphate
oxidized by the CrO3 in Fe : its value in Cr; or multiply the
value of the ferrous sulphate oxidized, in Fe, by 6f$1g* = .3103.

* Chem. News, xxxv. 151.
13

ANALYSIS OF IRON AND STEEL.

The titration is effected in the manner directed for the deter-
mination of iron in iron ores.

Barba * has suggested several modifications which decidedly

modifica-
tion, improve the method. To avoid the large precipitate of manganese

dioxide, he uses nitric acid to oxidize the iron, having found that
even a considerable excess of this reagent does not effect the
subsequent reactions. He uses, most successfully, ammonia to
destroy the excess of potassium permanganate. The method is
as follows :

Dissolve 1.25 grammes steel in 20 c.c. sulphuric acid 1.2
sp. gr. When solution is complete, add nitric acid drop by drop
until the iron is oxidized; 5 c.c. of nitric acid 1.2 sp. gr. is
generally sufficient.

Boil to remove nitrous fumes and add hot water, to bring the
volume to 150 c.c. ; add from a pipette, 5 c.c. of a saturated solu-
tion of potassium permanganate and boil briskly for 15 to 20
minutes; remove from the plate, wash down the sides of the
beaker to remove all permanganate, and add 25 c.c. strong
ammonia down the side of the beaker ; shake well and replace
on the cooler part of the plate, to avoid "bumping," of which
there is some danger if the heat be raised too rapidly. Shake
occasionally and digest for about 15 minutes, or until the per-
manganate is all decomposed, then add cautiously 20 c.c. dilute
sulphuric acid 1.58 sp. gr. and bring gently to boiling. Cool the
solution and pour into a graduated 250 c.c. flask. Make up to
mark with cold water, and mix well by pouring into a dry
beaker, back and forth a few times. Allow to settle and filter
through superposed funnels, with close, hard, dry filters, into
a dry beaker ; measure off 200 c.c. (equal to I gramme sample)
of the clear filtrate, and titrate by adding a known excess of
ferrous sulphate, and determining the excess by standard per-
manganate.

* The Iron Age, vol. Hi. p. 153.

DETERMINATION OF ARSENIC.

'95

FIG. 86.

DETERMINATION OF ARSENIC.

By Distillation.

Lundin * has suggested the following method of determining
arsenic, which gives very good results: Dissolve 10 grammes of
drillings in a large beaker in HNO3, 1.2 sp. gr., transfer the solu-
tion to a platinum or porcelain dish, add 50 c.c. H2SO4, and evap-
orate down until copious fumes of sulphuric acid are given off.
Cool the dish, add 50 c.c. of
water, and evaporate again until
the excess of H2SO4 is driven
off, and the ferric sulphate is so
dry that it can be readily trans-
ferred to a flask of about 500
c.c. capacity. Add to the mass
in the flask 1 5 grammes finely-
powdered ferrous sulphate,
pour in 150 c.c. strong HC1,
and close the flask with a
stopper carrying a tube bent
twice at right angles and con-
nected by a rubber tube with a
50 c.c. pipette, the point of which dips about y2 inch (12 mm.)
into 300 c.c. of water in a beaker, as shown in Fig. 86. Heat the
liquid in the flask gradually until it boils, and continue the dis-
tillation until the wide part of the burette becomes heated. The
arsenic acid in the solution is reduced by the ferrous sulphate,
and, in the strong hydrochloric acid solution, is distilled over as
AsCl3. Remove the light, disconnect the pipette, heat the solution
in the beaker to about 70° C, and pass a rapid current of H2S
through it until it is completely saturated. Remove the excess
of H2S by a current of CO2, and when the solution smells very

Reduction

* Jern-Kontorets Annaler, 1883, p. 360; Chem. News, li. 115.

j^6 ANAL YSIS OF IRON AND STEEL.

faintly of H2S, filter off the yellow precipitate of As2S3 in a Gooch
crucible4 or on a counterpoised filter,* wash with water, then with
alcohol, then with pure disulphide of carbon, dry at 100° C., and
weigh as As2S3, which contains 60.93 per cent, of As.

Or, after filtering the precipitate on the felt in a Gooch crucible,
transfer the precipitate and felt to a small beaker, add a little
fuming nitric acid, and, when action has nearly ceased, heat
gently until the sulphur is dissolved, dilute, filter, and evaporate
Determining down to about io c.c. Add 5 c.c. of magnesium mixture and
/^ the volume of the solution NH4HO. Stir the solution vigor-
ously from time to time, keeping it cool by immersing the beaker
in ice-water, and allow it to stand twelve hours. Filter on a
Gooch crucible, wash the precipitate of Mg2(NH4)2As2O8 -f- Aq
with the ammonia water containing nitrate of ammonium, used
for washing the Mg2(NH4)2P2O8 (page 85), dry at 103° C. for
half an hour, then increase the heat very gradually to redness,
and ignite strongly for a few minutes. Weigh as Mg2As2O7,
which contains 48.30 per cent, of As.

DETERMINATION OF ANTIMONY.

Antimony is a very rare constituent of iron or steel, but
very minute amounts have been found in Spiegel. To deter-
mine antimony, treat io grammes of the drillings as directed
for the determination of arsenic by precipitation with H2S, page
1 88. Evaporate off the excess of NH4HO from the filtrate from
the Mg2(NH4)2As2O8 -f Aq, add a slight excess of HC1, dilute
to about 300 c.c. with water, and pass a current of H2S through
the solution. Expel the excess of H2S by a current of CO2,
filter on a very small ashless filter, or on a disk of paper on
the bottom of a Gooch crucible, wash with water, and dry the
precipitate and filter. Separate the precipitate, and treat the fil-
ter in a small weighed porcelain crucible with fuming HNO3.

* See page 27.

DETERMINATION OF TIN.

When it is dissolved, evaporate down, add more HNO3 if neces-
sary, evaporate to dryness, and heat to destroy the organic mat-
ter. When the residue in the crucible is quite white, allow it
to cool, add the precipitate, and treat it with fuming HNO3,
evaporate to dryness, and finally ignite to drive off the sul-
phuric acid formed, cool, and weigh as Sb2O4, which contains
78.95 per cent. Sb. When tin is present, and the arsenic has separation
been precipitated from a sulphide of ammonium solution,* acid-
ulate the filtrate from the 'precipitate of Mg2(NH4)2As2O8 -{- Aq
with HC1, and when the solution smells but faintly of H2S, fil-
ter on a small ashless filter, wash with water, alcohol, and finally
with disulphide of carbon, dry the precipitate and filter, and
treat them with fuming HNO3, evaporate down, but not to dry-
ness, add an excess of dry Na2CO3, transfer the mass to a silver
crucible, add some pure fused NaHO, and fuse the whole for
some minutes. Allow the crucible to cool, dissolve the fused
mass in water, transfer it to a beaker, and add % the volume
of alcohol, .83 sp. gr. Stir several times, and allow the precipi-
tate of metantimonate of sodium to settle, filter, and wash with
a solution consisting of equal volumes of alcohol and water con-
taining a little Na2CO3 solution. The filtrate contains the tin, or
tin and arsenic. Dissolve the precipitate of metantimonate of
sodium on the filter in HC1 containing tartaric acid, allow the so-
lution and washings to run into a small beaker, dilute to about
300 c.c., and precipitate the sulphide of antimony by H2S. Fil-
ter off, and determine the antimony as Sb2O4 as above directed.

DETERMINATION OF TIN.

Tin is a most unusual constituent of steel or iron, but has
been found in the former in cases where scrap from tinned iron,

* The precipitated sulphides from acidulated KHS solution may be treated
directly in this way without precipitating the arsenic as Mg2(NH4)2As2O8 + Aq.

jgg ANALYSIS OF IRON AND STEEL.

from which the tin has been removed by a chemical process,
has been melted in the open-hearth furnace as a portion of. the
charge. Proceed as in the determination of antimony, until the
sulphides from the acidulation of the KHS solution have been
filtered on a small ashless filter and washed thoroughly with a
solution of acetate of ammonium made slightly acid with acetic
acid. It is not possible to wash the precipitate with water, as
the sulphide of tin has a strong tendency, under these circum-
stances, to pass through the filter. Dry the precipitate and filter,
transfer the precipitate to a weighed porcelain crucible, burn the
filter, and add its ash to the precipitate, add a little sulphur,
ignition m and ignite in a current of H2S, as directed for the determina-

HgS vola- ... .-, . . ...

tion of manganese as MnS, page 114. Any arsenic present will
be volatilized, but it is not possible to weigh the tin as sulphide,
as its composition is not constant. Heat the crucible carefully,
and roast the precipitate with access of air, heat it strongly two
or three times with carbonate of ammonium to volatilize any
sulphuric acid that may have been formed, cool, and weigh as
SnO2, which contains 78.81 per cent. Sn.

DETERMINATION OF TUNGSTEN.

Dissolve i to 10 grammes of the drillings in HNO3, 1.2 sp. gr.,
evaporate to dryness in the air-bath, redissolve in HC1, dilute
slightly, and boil for some time. The tungstic acid is deposited
as a yellowish powder. Dilute, filter, wash with hot water con-
taining a little HC1, and finally with alcohol and water. The pre-
cipitate consists of WO3 mixed with more or less SiO2, graphite,
and perhaps a little Fe2O3, TiO2, etc. Dry and ignite the filter
and precipitate, and burn off the carbon. Allow the crucible to
cool, moisten the precipitate with water, add a little H2SO4 and
an excess of HFL Evaporate to dryness under a hood, and
ignite to drive off the H2SO4. Fuse the residue with 5 times

tion as
mercurous

DETERMINATION OF TUNGSTEN.

its weight of Na2CO3, allow it to cool, dissolve in water, filter
from any insoluble matter, and wash with water containing a
little Na2CO3. The filtrate contains all the tungsten, as tungstate
of sodium. Nearly neutralize with HNO3, and boil off the CO2,
allow the solution to cool slightly, and add a faint but distinct
excess of HNO3. Add an excess of mercurous nitrate,* and
then mercuric oxide diffused in water,* until the free acid is all
neutralized. The tungsten is all precipitated as mercurous tung- Precipit
state, and can be washed perfectly free from all sodium salts with
hot water. Allow the precipitate to settle, filter on an ashless tungstate.
filter, wash with hot water, and dry the filter and precipitate.
Separate the precipitate from the filter, burn the filter in a plat-
inum crucible, add the precipitate, and heat it under a hood with
a good draft, increasing the heat gradually to a bright red. The
mercury volatilizes, and there remains only WO3. Cool, and
weigh as WO3, which contains 79.31 per cent, of W.

Rapid Method for Tungsten.

A rapid method for the determination of tungsten in high
tungsten steels and one that gives results sufficiently accurate
for ordinary work is as follows :

Treat one gramme of the steel in a No. 3 Griffin's beaker
with 25 c.c. of aqua regia, evaporate to dryness, redissolve in 10
c.c. strong hydrochloric acid, add I or 2 c.c. of strong nitric acid,
heat for a few minutes, dilute with hot water to 100 c.c., and
boil for ten minutes. Filter, wash with water containing a little
hydrochloric acid, and ignite. Treat the precipitate in the
crucible with a few drops of sulphuric acid and some hydro-
fluoric acid, evaporate to dryness, ignite, and weigh. Fuse the
precipitate with a little sodium carbonate, dissolve in hot water,
filter off the ferric oxide, wash it well with hot water, return it
to the crucible, ignite, and weigh. The difference between the
two weights is WO3.

* See page 56.

2QO ANALYSIS OF IRON AND STEEL.

DETERMINATION OF VANADIUM.

Vanadium is occasionally found in pig-iron, and may be deter-
mined with great accuracy by the following method : Treat 5
grammes of the drillings with 50 c.c. HNO3, 1.2 sp. gr., in a No. 4
beaker. When all action has ceased, transfer the liquid to a
porcelain dish, evaporate to dryness, and heat at a gradually in-
creasing temperature over a Bunsen burner until the nitrates are
nearly all decomposed and the mass separates easily from the
bottom and sides of the dish. Transfer the cooled mass to a por-
celain or agate mortar, and grind it thoroughly with 30 grammes
of dry Na2CO3 and 3 grammes of NaNO3. Transfer to a large
platinum crucible, and fuse well for about an hour at a high tem-
perature. Run the fused mass well up on the sides of the crucible,
allow it to cool, dissolve in hot water, and filter. Dilute the filtrate
to about 600 c.c., and add nitric acid carefully to get rid of the car-
bonic acid. Boil off the latter, but be careful to keep the solu-
tion always slightly alkaline. Filter, and to the filtrate add a few
drops of nitric acid to make it faintly acid, when the appearance

indication of a yellowish coloration is an indication of the presence of vanadic
acid. Add to the solution a few c.c. of mercurous nitrate,* and

Predpita- then an excess of mercuric oxide in water,* to render the solution
mercurous ncutralf and insure the complete precipitation of all the mer-
vanadate. curous vanadate. With the mercurous vanadate are precipitated
also all the phosphoric, chromic, tungstic, and molybdic acids as
mercurous salts. Heat to boiling, filter, and wash the precipitate.
Dry it, separate the paper, burn it in a platinum crucible, add the
precipitate, heat carefully to expel the mercury, and finally heat
to full redness. Fuse the brownish-red mass remaining in the
crucible with a small amount of Na2CO3 and a pinch of NaNO3,
dissolve the cooled mass in a small amount of water, and filter
into a small beaker. Add to the solution pure chloride of ammo-
nium in excess (about 3.5 grammes to each 10 c.c. of solution),

* See page 56. f Am. Chem. Jour., v. 373.

DETERMINATION OF NITROGEN. 2OI

and allow it to stand for some time, stirring occasionally. Vana- Predpita-
date of ammonium, insoluble in a saturated solution of chloride vanadate
of ammonium, separates out as a white powder. It is necessary m0nium.
to keep the solution decidedly alkaline, and a drop or two of am- Precautions,
monia must be added from time to time. The appearance of the
faintest yellowish tint to the solution is evidence that the solution
has become slightly acid, and this must be corrected or the result
will be too low. Filter on a small ashless filter, wash first with a
saturated solution of chloride of ammonium containing a drop or
two of ammonia, and then with alcohol. Dry, ignite, moisten with
a drop or two of nitric acid, ignite, and weigh as V2O5, which
contains 56.22 per cent, of vanadium.

DETERMINATION OF NITROGEN.

This method is based on the reaction by which the nitrogen
in iron or steel is converted into ammonia by HC1 during the
solution of the steel in this reagent.

It was first published by A. H. Allen,* with many interest-
ing details and results. The modifications of the method as
described by Mr. Allen are by Prof. J. W. Langley,f of Pitts-
burg, and consist essentially in the use of caustic soda freed from
nitrates and nitrites by the copper-zinc couple and subsequent
distillation of all ammonia formed, and in a few details of
manipulation.

The reagents required are:

Hydrochloric Acid of i.i sp. gr., free from Ammonia, which pure HO.
may be prepared by distilling pure hydrochloric acid gas into
distilled water free from ammonia. To do this, take a large flask
fitted with a rubber stopper carrying a separatory funnel-tube
and an evolution-tube, fill it half-full of strong hydrochloric

* Chem. News, xli. 231. •}• Communicated to the author.

2Q2 ANALYSIS OF IRON AND STEEL.

acid, connect the evolution-tube with a wash-bottle connected
with a bottle containing the distilled water. Admit strong sul-
phuric acid free from nitrous acid to the flask through the funnel-
tube, apply heat as required, and distil the gas into the prepared
water.

Test the acid by admitting some of it into the distilling appa-
ratus, described farther on, and distilling it from an excess of pure
caustic soda, or determine the amount of ammonia in a portion
of hydrochloric acid of i.i sp. gr., and use the amount found
as a correction.

Caustic Solution of Caustic Soda, made by dissolving 300 grammes

of fused caustic soda in 500 c.c. of water, and digesting it for
twenty-four hours at 50° C. on a copper-zinc couple, made, as
described by Gladstone & Tribe, as follows : Place 25-30 grammes
of thin sheet zinc in a flask and cover with a moderately-con-
centrated, slightly warm solution of sulphate of copper. A thick
spongy coating of copper will be deposited on the zinc. Pour
off the solution in about ten minutes and wash thoroughly with
cold distilled water.

Nessier Nessler Reagent. Dissolve 35 grammes of iodide of potas-

sium in a small quantity of distilled water, and add a strong
solution of bichloride of mercury little by little, shaking after
each addition, until the red precipitate formed dissolves. Finally
the precipitate formed will fail to dissolve, then stop the addition
of the mercury salt and filter. Add to the filtrate 120 grammes
of caustic soda dissolved in a small amount of water, and di-
lute until the entire solution measures I litre. Add to this 5
c.c. of saturated aqueous solution of bichloride of mercury, mix
thoroughly, allow the precipitate formed to settle, and decant
or siphon off the clear liquid into a glass-stoppered bottle.

standard Standard Ammonia Solution. Dissolve 0.0382 gramme of

solution chloride of ammonium in I litre of water. One c.c. of this so-
lution will equal O.OI milligramme of nitrogen.

Distilled Water free from Ammonia. If the ordinary dis-

DETERMINATION OF NITROGEN. 203

tilled water contains ammonia, redistil it, reject the first portions Ammonia-

free

coming over, and use the subsequent portions, which will be distnied
found free from ammonia. Several glass cylinders of colorless
glass of about 1 60 c.c. capacity are also required.

The • best form of distilling apparatus consists of an Erlen- Distn-
meyer flask of about 1500 c.c. capacity, with a rubber stopper, paratus.
carrying a separatory funnel-tube and an evolution-tube, the lat-
ter connected with a condensing-tube through which a constant
stream of cold water runs. The inside tube, where it issues
from the condenser, should be sufficiently high to dip into one
of the glass cylinders placed on the working-table.

The determination of nitrogen is made as follows : Place 30 Details
c.c. of the caustic soda, which has been treated with the cop- method
per-zinc couple, in the Erlenmeyer flask, add 500 c.c. of water,
and distil until the distillate gives no reaction with the Nessler
reagent. While this part of the operation is in progress, dissolve
3 grammes of the carefully-washed drillings in 30 c.c. of the
prepared hydrochloric acid, using heat if necessary. Transfer
the solution to the bulb of the separatory funnel-tube, and when
the soda solution is free from ammonia drop the ferrous chlo-
ride solution into the boiling solution in the flask, very slowly.
The ferrous hydrate formed is apt to stick to the bottom and
sides of the flask and cause it to break. When about 50 c.c.
of water has been collected in the cylinder, remove it and sub-
stitute another cylinder. Dilute the distillate in the cylinder to
100 c.c. with the special distilled water, and add \y2 c.c. of
Nessler reagent. Take another cylinder, pour into it 100 c.c.
of the special distilled water, add I c.c. of the chloride of am-
monium solution and I j£ c.c. of the Nessler reagent. Compare
the colors in the two cylinders, and add ammonia solution to the
contents of the latter cylinder until the colors of the solutions
in the two cylinders correspond after standing about ten minutes.
When about 100 c.c. has distilled into the second cylinder, re-
place it and test it as before. Continue the distillation until

2O4 ANALYSIS OF IRON AND STEEL.

the water comes over free from ammonia, then add together
the number of c.c. of ammonia solution used, divide the sum
by three, and each o.oi milligramme will be o.ooi per cent, of
nitrogen in the steel.

DETERMINATION OF IRON.

The combined carbon in steel and iron interferes with a direct
determination of the amount of metallic iron by solution of the
drillings in hydrochloric or sulphuric acid and direct titration.
It is always necessary to oxidize the iron and carbonaceous matter
in the solution, and the process may be carried out as follows:

By solution. Dissolve .5 gramme of the drillings in a small flask, as described
for the determination of iron in iron ores, in HC1, add KC1O3 in
small crystals until the iron is all oxidized and an excess of KC1O3
is present, boil until all the yellow fumes have disappeared, and
then proceed as in the determination of iron in iron ores, page
207. Instead of chlorate of potassium, permanganate of potassium
or chromic acid may be used to oxidize the iron and destroy
the carbonaceous matter. In pig-irons the most satisfactory

By fusion, method is to fuse .5 gramme of the borings in a large platinum
crucible with 10 grammes Na2CO3 and 2 grammes KNO3, dissolve
in hot water, transfer to a small beaker, allow the ferric oxide to
settle, decant on a small filter, and wash several times by decanta-
tion. After the last decantation, remove the beaker containing the
filtrate and place the beaker containing the ferric oxide under the
funnel. Dissolve any adhering oxide in the crucible with HC1,
dilute slightly, and pour it on the filter to dissolve the small
amount of oxide, allowing the solution to run into the beaker.
Wash the filter if necessary, add more HC1 to the solution in the
beaker, evaporate down, transfer to a small flask, deoxidize, and
titrate as before. In the case of puddled iron, it is necessary to
subtract the iron in the " slag and oxides" from the total iron ob-
tained as above to get the amount of metallic iron in the sample.

METHODS FOR THE ANALYSIS

IRON ORES.

A FEW words in regard to the proper method of taking Method of
samples of iron ores may not be amiss, for unless the sample iron ores,
truly represents the lot from which it' is taken, the subsequent
work of the analyst is useless, if not misleading.

In drawing a sample, note carefully the relative amounts of
fine ore and lumps in the lot to be sampled, and see that this
proportion be observed in the whole amount taken. A small
trowel may be used for taking the fine ore, and only about a
teaspoonful should be picked up at one time. In taking pieces
from the lumps, it will never do to merely chip the outside, but
each lump as selected should be broken and chippings taken
from both the inside and the outside, and no piece taken should
be larger than a cherry. In sampling from cars or wagons these
points should be observed in each car or wagon, for it is rarely
the case that the ore even from one mine is so uniform as to render
this precaution unnecessary. In some cases the lumps are covered
with dirt or gangue, making the outside of the lump poorer in
iron than the inside, and on the other hand the lumps are merely
masses of dirt coated with ore. Then the fine stuff may be much
richer than the lumps, or it may be merely dirt or gangue, while
it almost always contains more hygroscopic water than the lumps.
The sample should be taken in tin cans with close-fitting lids, Preserving
and the amount should be proportioned to the size of the lot

sampled. Two pounds to ten tons is a good rule for large lots.

205

2O6

ANALYSIS OF IRON ORES.

DETERMINATION OF HYGROSCOPIC WATER.

Break the sample down quickly to about pea size, mix thor-
oughly in a large glazed earthenware or metal dish, and weigh out
from y2 to I kilo, into a copper box about 4^ inches (114 mm.)
long, 3^ inches (95 mm.) wide, and ij^ inches (38 mm.) deep,
and dry in a water- or air-bath at 1 00° C. for at least twelve hours,
or until it ceases to lose weight. Fig. 87 shows a convenient form

FIG. 87.

Device for
constant
level.

of water-bath. The boxes are numbered, and each one is pro-
vided with a counterpoise stamped with the same number as the
box, to facilitate the weighing. When a supply of water is not
available to run the constant level shown in Fig. 87, the device,
on the principle of Marriott's flask, as shown in Fig. 78, page 169,

DETERMINATION OF TOTAL IRON.

207

may be used. The position of the end b of the tube a fixes the
level of the water in the bath.

A balance sensitive to .1 gramme is sufficiently accurate for Balance for
weighing these samples. The loss of weight in grammes divided samples.
by 5, when j£ kilo, of ore was originally used, gives the percentage
of hygroscopic water in the sample. Grind the dried sample very
fine, mix it well, heat as much of it as may be required for the
analysis, in the water-bath, and put it while still hot into a per-
fectly dry, glass-stoppered bottle.

DETERMINATION OF TOTAL IRON.

Very few iron ores are completely decomposed by hydro- Residue
chloric acid, the insoluble residue usually containing more or less faHca.
iron, as silicate, titaniferous iron, etc. The disregard of this fact
may occasion grave errors in the determination of iron, and,
unless a previous examination has shown the absence of iron in
the insoluble residue, it is best to proceed as follows : Weigh I Treatment
gramme of the finely-ground sample into a No. I beaker, add 10
c.c. HC1, and digest it on the sand-bath until the residue appears
quite white and flotant, or until the acid appears to have no
further action. When the ore contains carbonaceous matter, add
a little KC1O3. Wash off the watch-glass with a fine jet of water,
remove it, and evaporate to dryness in the air-bath. Redissolve
in about 5 c.c. HC1, dilute with 10 c.c. water, allow to settle, and
decant the clear liquid into a flask (B, Fig. 89) of about 50 to 75
c.c. capacity. Transfer the residue to a small filter, fitted in a
funnel placed in the neck of the flask, with as little water as pos- Treatment
sible, and wash with cold water from a fine jet. Transfer the filter of*? in'

soluble

to a small platinum crucible, burn it off, allow the crucible to cool, residue

by H2S04

and pour on the residue 20 or 30 drops of H2SO4 and about twice and HFI.

2o8 ANALYSIS OF IRON ORES.

as much HF1. Heat carefully, and, if the residue is dissolved, evap-
orate off the HF1, allow the liquid to cool, and dilute slightly,
when it will be ready to add to the solution in the flask, which
shall have been deoxidized in the mean time by one of the
methods explained farther on.

Occasionally this treatment fails to decompose the insoluble

residue, in which case it is necessary to heat the crucible until

the greater part of the H2SO4 shall have been driven off; then

Treatment add about .5 gramme KHSO4, and heat gradually until the

with

KHS04. KHSO4 is quite liquid and fumes of SO3 are given off whenever
the lid of the crucible is raised. When all the black specks have
disappeared, allow the crucible to cool, and dissolve the salt in
the crucible with hot water and a few drops of HC1.

Several methods are used for the deoxidation of the solution
of ferric chloride, but the one in general use is by adding metallic
zinc to the solution. The iron is deoxidized according to the
reaction Fe2Cl6+ Zn = 2FeCl2-f ZnQ2, while the excess of HC1
is decomposed and hydrogen liberated, 2HC1+ Zn = ZnCl2-f 2H.
As all zinc contains a small amount of iron, the amount added to
the solution should be roughly weighed. Add then to the solu-

metallic tion in the flask 3 grammes of granulated zinc,* and, when the
evolution of hydrogen has somewhat slackened, heat the flask
slightly. The neck of the flask is closed by a small funnel, which
allows the hydrogen to escape while the liquid is caught on the
funnel and falls back into the flask. It sometimes happens as the
solution becomes neutralized that a basic salt of peroxide of iron
is thrown down, giving the solution a reddish color ; in this case
add a few drops of HC1, and when the solution finally becomes

End of the colorless add a few drops more of HC1. If this fails to produce a
yellowish coloration, the solution may be considered deoxidized.

Final addi- Pour in through the funnel the solution of the residue insoluble in
H2so4. HC1, and add gradually a mixture of 10 c.c. H2SO4 and 20 c.c.

* See page 57.

DETERMINATION OF TOTAL IRON. 2OQ

H2O. This addition of H2SO4 is a very necessary part of the
operation, for it not only serves to dissolve the remainder of the
zinc which is unacted on when the deoxidation is complete, but it
supplies the proper amount of sulphate of zinc and iron, which
makes the end reaction with permanganate of potassium as sharp
as if no HC1 were present in the solution. As soon as all the
zinc is dissolved, wash down the funnel inside and out and the
neck of the flask with a fine jet of water, filling the flask almost
full, cool the flask in water, and when the solution is quite cold
transfer it to a large white dish of about 1500 c.c. capacity (see A,
Fig. 89, page 214). Wash the flask and funnel well with cold
water, pour the rinsing into the dish, and make the solution up to
about 1000 c.c. Run in from a burette a standard solution of Titratkm by

£ perman-

permanganate of potassium (Marguerite's method), the value of ganate
which has been carefully determined by one of the methods de-
scribed farther on. At first the color of the permanganate is
destroyed almost as soon as it touches the liquid in the dish, which
should be stirred carefully with a glass rod. The permanganate
should be added more and more slowly until towards the end of
the operation it is added only drop by drop. The liquid in the
dish gradually assumes a yellowish tint, which is deeper the
larger the amount of iron jn the ore. Finally a drop of the per-
manganate seems to destroy the yellow color, and the next drop
gives the liquid a very faint pink tinge. This is the end of the
reaction. Take the reading of the burette, and then add another
drop, which will cause the solution to become decidedly pink in
color. The number of c.c. of the standard solution used when
the reading was taken, less a small correction for the zinc, etc.,
noted farther on, multiplied by the value of I c.c., gives the
amount of metallic iron in the ore.

The reductor, Fig. 88, is also useful for reducing ferric salts to Jones's
ferrous ; the only disadvantage is that it seems necessary to have
the iron present as sulphate, which necessitates evaporating off the
hydrochloric acid used in dissolving ores. The description of the

210

ANALYSIS OF IRON OKES.

reductor and the method of using it in iron determinations is as
follows : *

The conditions essential to the accurate determination of
iron by this method are : That the iron must be in the state
of ferric sulphate ; that the solution of ferric sulphate must be
dilute; that the least traces of hydrochloric and nitric acids
must be absent. There should not be over 50 c.c. sulphuric
acid, 1.32 sp. gr., in 300 c.c. of the ferric solution ready for re-
duction.

For iron ores, and in almost all cases, this ordinarily pre-
sents no difficulties. If the solution is in strong sulphuric acid,
it must be reduced in bulk, or diluted to such an extent as to
avoid violent action in contact with zinc. The volume of the
solution should not exceed 350 c.c.

Preparing The reductor should now be filled with zinc and washed as

ductor. required. If there is still enough zinc remaining in the tube
from previous reductions, a single washing will usually suffice.
The ferric solution is now brought to the reductor and trans-
ferred to one or both of the cups A and B, washing out the
beaker or flask three or four times with water.

Details of The stopcock G of the reductor is opened, and the two-way

stopcock C is set to discharge the solution, which is then filtered
through the zinc. The cup is then rinsed out five times with
water as described. The stopcock G is then closed to relieve
the pressure, and the flask F is detached. The solution has
now a volume of about 400 to 500 c.c. In this manner a solu-
tion of ferric sulphate is instantaneously and completely reduced
in two minutes. The burette is now filled to the zero mark as
described, and the solution is titrated in the flask direct.

A little practice will enable the operator to give a continuous
circular motion to the flask held in the right hand, with the left
hand in control of the flow of the permanganate from the burette.

* Prepared by Mr. Clemens Jones for this volume.

DETERMINATION OF TOTAL IRON.

211

The average time by this means for the reduction and accu-
rate titration of a ferric solution is four minutes. The burette Description
B (50 c.c. to ^ c.c.), shown in Fig. 88, consists of the gradu-

FIG. 88.

ated glass tube proper, and an arm, E, fused to it, below the
50 c.c. mark. At its top are rubber connections with the blast-
aspirator, shown in the cut. By means of the stopcock D con-

ANALYSIS OF IRON ORES.

nection through E is established with the glass reservoir F.
The burette is clamped securely to a slide, C, which is coun-
terpoised, and moves freely on guides between two parallel sides,
L, L, suitably mounted in a frame, and through their whole
length.

Back of the burette a porcelain scale may be fixed, graduated
to correspond with it, and secured to the slide, in front of which
the burette may be adjusted. The reservoir F is suspended in
a shelf placed within the frame, and is introduced into the side-
door K, shown open, and is then encased in a box, which has
an annular hole in the top to admit the prong of the tube E,
the slide C being previously raised. The reservoir is so placed
that when the slide is at the lowest point the inlet-prong has
a safe margin from the bottom.

If a float is used, it remains in the burette permanently, and
is caught on a stage of fine platinum wire supported by a spiral,
when it descends within one-half inch of the inlet-tube. In
Reservoir operation, the reservoir F, containing about two litres, is filled
with the solution of permanganate and placed in position ; the
slide C is lowered until the zero marks are brought in the di-
rect line of vision; blast is admitted to the aspirator by the
brass valve V, and the suction produced is communicated to the
burette, both stopcocks, H and D, being closed.

When the float is used, the stopcock H is first opened, the
suction lifting the float to the zero mark in the burette. Stop-
cock H is then closed, and, while the float slowly descends, stop-
cock D is opened, admitting the permanganate solution and
allowing the float to sink without enclosing any bubbles of air.
The burette is then filled exactly to the zero mark. In titration,
the blast must, of course, be shut off, and the column of solution
connected with the outside atmosphere by turning a suitably-
arranged stopcock of the aspirator. If the float is not employed,
stopcock H remains closed, and by opening stopcock D the
burette is filled in the manner described above.

manganate
solution.

DETERMINATION OF TOTAL IRON.
To cleanse the burette, allow the solution partially filling it Method of

„. , TT . - cleaning

to run out. Stopcock H is then closed, suction is again pro- burette,
duced by starting the aspirator as described, and a beaker of
water is held so that the burette tip is in the water. On open-
ing the ' stopcock H, the water rises in the burette. This is then
run out by again stopping the aspirator, and the operation is
repeated until the burette is perfectly clean. Should the burette
require further cleansing, hydrochloric acid may be used in the
same manner. This is then washed out with water as before,
and the burette may then be dried in a few minutes by turning
on the blast gently, and reversing the aspirator by simply closing
its main outlet with a rubber cap, allowing the current of air to
pass down through the burette and out through the open stop-
cock H. By closing the outside doors the apparatus is protected
from light. The apparatus is always ready for use. Twenty ac-
curate titrations can be easily made in an hour's time.

The simple form of reductor, Fig. 52, shown on page 96,
may be used for deoxidizing the solution of the ore in which the
iron is in the form of sulphate. With amalgamated zinc it is a
most excellent and rapid device. The method of reduction is
given on page 98 in the description of the method of standard-
izing the potassium permanganate solution.

Another form of burette which is extremely convenient and Another

form of

has the great advantage of dispensing with the glass stopcock, burette;
which is liable to stick at a critical moment, or break without
warning, is shown in Fig. 89.

The burette is attached to the wooden stand by bands of
German silver or of nickel. The top of the burette is closed
by a rubber stopper carrying a glass tube of small bore con-
nected by rubber tubing with a small glass tube attached to the
back of the burette-stand. To the end of this tube, near the
base of the burette-stand, is attached a short piece of heavy-
walled gum tubing, a, passing under a compressor fixed to the
base of the stand. Fig. 90 shows the form and construction of

214

ANALYSIS OF IRON ORES.

FIG. 89.

the clamp or compressor. By applying suction at the end of
the tube b the standard solution may be drawn up into the
burette a little above the zero mark, and the compressor closed

down on the tube a,
holding the liquid in
the burette until the
admission of air through
the tube a allows the
liquid to flow out of
the burette. The entire
practical value of this
burette * depends on
placing a drop or two
of water in the tube «,
which, flowing to the
point of compression,
not only closes the tube
hermetically when the
clamp is screwed down,

FIG. 90.

Method of Dut makes it possible, by a slight movement of the clamp, to

controlling

the flow of admit the smallest quantity of air to the burette, and thus to
permit the liquid to flow from the burette at any desired rate.
The flow is thus controlled by the left hand while the solution in
the dish is stirred with the right. Towards the end of the opera-

The suggestion of Mr. Thos. H. Garrett, of Philadelphia

DETERMINATION OF TOTAL IRON. 215

tion a single drop may be made to flow from the burette, when
the clamp is closed (not too tightly), by compressing the tube a
at the point c with the thumb, and forcing a little air into the
burette. Even a fraction of a drop may be obtained by touching
the point of the burette with the stirring-rod. The scale shown
in the sketch is fixed on the wall, so that the eye may always be
kept at the proper level in taking the readings of the burette.

When usiner a standard solution of bichromate of potassium Thration

with bi-

(Penny's method), the end reaction is not rendered apparent by a chromate
change in the color of the solution, but the presence or absence sium.
of ferrous salt in the solution is determined by taking a drop from
the dish on the end of the stirring-rod and allowing it to run into
a drop of a dilute, freshly-made solution of ferricyanide of potas-
sium placed on a white tile or capsule. Dissolve a very small
crystal of ferricyanide of potassium in a few c.c. of water, and
place a number of drops of the solution on a white tile or on a
flat-bottomed capsule. Run the carefully standardized solution
of bichromate of potassium from the burette into the deoxidized
iron solution previously placed in a white dish. The solution, at
first colorless, changes gradually to a decided chrome-green from
the reduction of "the chromic acid. Test the progress of the oxi-
dation of the iron solution by transferring a drop of it on the end
of the stirring-rod to one of the drops of ferricyanide. As the
blue color produced becomes less intense, add the bichromate
more slowly and make the test more frequently, towards the end
of the operation after the addition of each drop of bichromate.
When, finally, no color appears in the test-drops, even after the End of the

reaction.

lapse of several moments, the oxidation of the ferrous salt is
complete, and the amount of bichromate used, less a small cor-
rection for the zinc, is the measure of the amount of iron in the
ore. The ferricyanide of potassium employed must, of course, Purity of

ferricy-

be perfectly free from ferrocyanide : it may be tested by adding anide.
a drop of ferric chloride solution to one of the drops of ferri-
cyanide solution, the absence of any resulting blue color in the

2I5 ANALYSIS OF IRON ORES.

test-drops being proof of the purity of the ferricyanide. As
deteranhia- towards the end of the operation the frequent tests become rather
tedious, some analysts prefer to make the determinations in dupli-
cate, using the first to get an approximate result.
Treatment When the ore is completely decomposed by HC1, a separate

or ores r •

completely treatment of the residue is unnecessary, and the ore may be
poseTby weighed at once into the flask and treated with 10 c.c. HC1
and a little KC1O3 when organic matter is present. When the
ore is completely decomposed, and any Cl from the KC1O3
driven off, add 30 c.c. of water, and proceed with the deoxida-
tion.

Instead of deoxidizing the solution of ferric chloride by zinc, it

NH4Hso3. may be deoxidized by a solution of bisulphite of ammonium. In

fact, the deoxidation by zinc is not practicable in ores containing

inthepres- much TiO2, for the TiO2 is reduced by metallic zinc to Ti2O3, im-

ence of

Tio2. parting a purple or blue color to the solution, and acting like a
solution of ferrous salt on the standard solution of permanganate.
In deoxidizing a solution of ferric chloride by this method it
should be placed in a flask of 120 c.c. capacity, and two or three
small spirals of platinum wire added to facilitate the subsequent
boiling. Add cautiously to the solution (which should not exceed

Details

of the 40 c.c. in volume) enough ammonia to produce a slight permanent

method.

precipitate of ferric hydrate, which remains even after vigorous
shaking. Add now 5 c.c. of a strong solution of NH4HSO3,*
shake vigorously, and warm the flask gently. As the color of
the solution — at first a deep red — fades, increase the heat, and
finally heat to boiling. When the solution is quite colorless, add
to it the solution of the residue and 100 c.c. H2SO4 mixed with
20 c.c. H2O. Boil the solution until all the sulphurous acid is
driven off. When the escaping steam no longer smells of SO2,
place the flask in cold water, wash down the funnel and the neck
of. the flask, filling the latter quite full of water, and when the

* See page 44.

DETERMINATION OF TOTAL IRON.

solution is quite cold transfer it to a dish and titrate with a
standard solution.

A third method of deoxidizing the solution of ferric chloride

by SnCl2.

is used, in which the reducing agent is a solution of stannous
chloride. The investigations of Zimmerman* and Reinhardtf
have made this method of reduction a favorite one, especially
when, by the use of phosphoric acid and manganous sulphate,
the subsequent titration with potassium permanganate is practica-
ble. The details are as follows : Prepare the following solutions :

1. Phosphoric acid solution: Dissolve 200 grammes of
crystallized manganous sulphate in I litre of water, add a few
drops of sulphuric acid, and filter. Add to this I litre of phos-
phoric acid (1.3 sp. gr.), 600 c.c. water, and 400 c.c. strong sul-
phuric acid.

2. Stannous chloride solution: Dissolve 120 grammes of
granulated tin, free from iron, in 500 c.c. hydrochloric acid (1.19
sp. gr.), dilute to I litre, and filter through asbestos. To the
filtrate add I litre of hydrochloric acid (1.124 SP- gr-) and 2 litres
of water.

3. Mercuric chloride solution : Dissolve 50 grammes of
mercuric chloride in I litre of water and filter.

Dissolve I gramme of the ore in 30 c.c. strong hydrochloric
acid (if necessary, ignite, and fuse the residue with a little sodium
carbonate, dissolve in water and hydrochloric acid, and add to the
main solution), transfer to a 150 c.c. Erlenmeyer flask, heat to
boiling, and add, from a burette, stannous chloride solution until
the color of the solution fades completely. Pour into the dish
(page 214) 600 c.c. of water and add to it 60 c.c. of the phos-
phoric acid solution. To the deoxidized solution in the flask
add 60 c.c. of the mercuric chloride solution, pouring it all in at
once, shake vigorously and wash the solution out into the dish,
using plenty of wash water, and titrate with permanganate in

* Berichte d. Chem. Ges., 1884, xv. 779.
f Chem. Zeit., xiii. 324.

2i 8 ANALYSIS OF IRON ORES.

the usual way. The phosphoric acid makes the solution nearly
colorless by forming ferric phosphate, and the end reaction is very
sharp.

The mercuric chloride should not be added until everything
is ready for the titration, as the absence of any deoxidizing sub-
stance may cause the solution to become slightly oxidized on
standing.

Mixer and Dubois* give several modifications of the method
as used in the Lake Superior region. They use a solution of
potassium permanganate of such strength that I c.c. equals two
per cent, of iron when one-half gramme of ore is used. They
use for standardizing the permanganate an iron ore the amount of
iron in which is accurately known, and if the permanganate is not
exactly of the proper strength, they use such a weight of the ore,
approximating 0.5 gramme, that the reading of the burette multi-
plied by 2 gives the percentage of iron. Necessarily this implies
the use of the same weight of the ore to be analyzed. They also
add to the ore about 2.5 c.c. of a 25 per cent, solution of stannous
chloride before adding the hydrochloric acid, as this is said to
very much hasten the solution of the ore.

Methods for Standardizing the Solutions.
It is of the utmost importance that the value of the standard
affecting solution employed should be determined with the greatest accu-
racv *f t^le results obtained by its use are to be anything but mere
approximations. To do this, not only should the reagents em-
the stand- ployed be pure, but the conditions under which the standard is

ard

fixed should be, as nearly as practicable, those under which it is
employed in actual use. The conditions referred to are not only
those of temperature, dilution, etc., but of the actual chemical
composition of the liquid acted on by the standard solution by
which its value is determined.

The best reagent to employ is a solution of ferric chloride

* Journal of the American Chem. Soc., vol. xvii. p. 405.

DETERMINATION OF TOTAL IRON.

2I9

of known strength. To prepare this, dissolve 100 grammes of
wrought iron (free from manganese and arsenic, and in which the
phosphorus has been accurately determined) in nitric acid, evapo-
rate to dryness in a capsule, and heat until the nitrate of iron is
largely decomposed and the mass separates easily from the bottom
and sides of the capsule. Transfer to a piece of platinum-foil
with the edges turned up, and heat for some time in a muffle
at a very high temperature, or heat it, a portion at a time, in a
crucible at the highest temperature obtainable by a blast-lamp.
Grind the entire mass very fine in an agate mortar, dissolve in
HC1, evaporate to dryness, redissolve in dilute HC1, filter to get
rid of SiO2, and dilute the solution to about 4 litres. Twenty c.c.
of this solution will contain about .5 gramme Fe, and it may be
kept indefinitely in a glass-stoppered bottle sealed with paraffine,
or after being thoroughly mixed it may be preserved in a number
of smaller bottles properly secured.

Wash out and dry thoroughly three of the small flasks used
for deoxidizing the solutions of the ores, weigh them to within
I mg., and measure into each a portion of the ferric chloride
solution ranging from 15 to 25 c.c. in volume. Weigh the flasks
and their contents ; the differences between the first and second
weights are the weights of the ferric chloride solution taken.
Transfer the solution carefully from each flask to a platinum dish,
dilute, boil, precipitate by NH4HO, filter, wash, dry, ignite, and
weigh the precipitate with the precautions mentioned farther
on. The precipitate is Fe2O3 -f P2O5. Subtract from this weight
the amount of P2O5 in this weight of the material, and the remain-
der will be the weight of Fe2O3 in the amount of solution used.
Suppose, for example, that the original iron contained .1 per cent.
P, this would be equivalent to 0.229 Per cent. P2O5, but, as the iron
has been oxidized to Fe2O3, the percentage of P2O5 in the iron as
oxide would be only ^ as great as in the iron itself, the weight as
oxide being ^ as great as it was as Fe. Therefore multiply .229
per cent, by .7 for the percentage of P2O5 in the Fe2O3, which

Preparation

of ferric

chloride

thes

strength '

solution.

Example

JrateThe
method-

220 ANALYSIS OF IRON ORES.

gives .16 per cent. P2O5. If we further suppose that the weight of
Fe2O3-hP2O5 obtained was .8131 gramme, .16 per cent, of this
would be .0013 gramme, the weight of P2O5 in the precipitate,
and .8131 — .0013 = . 8118 gramme, the weight of Fe2O3 in the
amount of solution taken. Divide this weight by the weight of
the solution, and the result is the weight of Fe2O3 in I gramme
of the solution of ferric chloride. Take the mean of the three
results obtained in this way, and call this result the value of
the ferric chloride solution in Fe2O3, or multiply by .7 for its
value in Fe.

To standardize the permanganate or bichromate solution,
weigh out three portions of the ferric chloride solution into the
flasks, reduce them by the method selected, and titrate the re-
duced solutions exactly as directed above. Before calculating the
strength of the standard solution a small correction must be ap-
plied to the burette reading, due to the fact that a definite amount
of oxidizing solution is required to produce the end reaction in
all cases where permanganate is used, and, when bichromate
is used, in those cases where zinc has been the deoxidizing
agent.
Determina- Treat 3 grammes of zinc in a small flask with 5 c.c. HC1 and

tion of

the cor- 20 c.c. H2O, add gradually 10 c.c. H2SO4 and 20 c.c. H2O. When
for zinc, the zinc has all dissolved, place the flask in cold water until the
solution is cold. Wash it out into the dish, dilute to I litre, add
20 c.c. ferric chloride solution (free from ferrous salt), and drop in
the standard solution until the end reaction is obtained. Subtract
the correction thus obtained from every burette reading. To
calculate the strength of the standard solution, therefore, subtract
the correction from the burette reading, and the result is the
absolute volume of the standard solution required to oxidize the
ferrous salt in the solution operated on. Knowing then the
weight of the ferric chloride solution used, the amount of Fe in
each gramme of the solution, and the volume of the standard
required to oxidize this amount, the value of each c.c. of the

DETERMINATION OF TOTAL IRON. 221

standard solution is found by multiplying the weight of ferric Calculation
chloride solution used by the value of each gramme in Fe, and value
dividing the amount by the number of c.c. of the standard used standard
in titrating. The mean of the results obtained in the three por-
tions used should be taken as the value of the standard solution.
An example will illustrate the method of computation, and, as
logarithms very much facilitate these calculations, they will be
given in the example as well.

Weight of empty flask 22.8817 Example of

Weight of flask -f- ferric chloride solution 40.0640

Weight of ferric chloride solution used 17.1823 = ^.1.2350813

Value of ferric chloride solution, determined as on

p. 219 i gramme = .03227 gramme Fe = log. 8.5087990 — 10

Fe in ferric chloride solution used 55448 gramme = log. 9.7438803 — IO

Burette reading after titration =82.0 c.c.

Less correction 0.25

Corrected reading 81.75 c.c. =r log. 1.9124878

I c.c. standard solution — .0067826 gramme Fe =log. 7.8313925 — 10

Of course in calculating the amount of Fe in an ore it is only calculation
necessary to get the logarithm of the corrected reading (page 220) Lore"1
and add it to the logarithm of the standard solution as found
above, the number corresponding to the resulting logarithm being
the weight of Fe in grammes in the ore. This multiplied by 100
will give the percentage.

Very fine iron wire may be used to standardize the solutions, Use of iron
instead of a standard solution of ferric chloride. Weigh into the standard-
reducing flasks from .4 to .6 gramme of fine iron wire (page 55)
which has been carefully rubbed with fine sand-paper and wiped
clean with a linen rag. Dissolve in 10 c.c. HC1 and 20 c.c. H2O,
with the addition of a few small crystals of KC1O3. Deoxidize
carefully, and titrate as before directed. Multiply the weight of
iron wire by .998 to get the absolute amount of Fe used, apply
the proper correction to the burette reading, and calculate the
value of the standard.

222

ANALYSIS OF IRON ORES.

Use of fer-
rous sul-
phate or
ammonio-
ferrous
sulphate.

Degree of
concen-
tration of
standard
solutions.

Preparation
and pres-
ervation of
solutions.

Ferrous sulphate, FeSO4,7H2O,* containing 20.1439 Per cent.
Fe, or the double sulphate of iron and ammonium FeSO4,(NH4)2
SO4,6H2O,f containing 14.2857 per cent, or almost exactly \ of
its weight of Fe, may be used instead of ferric chloride solution or
iron wire to determine the value of the standard solutions. The
pure salts are generally weighed off, dissolved in water with 10 c.c.
H2SO4, added and titrated direct, but they are not so satisfactory
in use as the first and second methods described. It is important
to have the standard solutions of the proper strength ; that is,
neither too dilute nor too concentrated for convenience in work-
ing. As iron ores rarely contain more than 60 per cent, metallic
iron, a standard solution 100 c.c. of which are equal to .66
gramme Fe will be found sufficiently concentrated to avoid the
necessity of refilling the burette for a determination ; and where
ores much poorer than this are habitually used the solutions may
be correspondingly more dilute.

When permanganate of potassium is added to a solution of
ferrous sulphate the reaction is ioFeSO4 + 2KMnO4 -f 8H2SO4 =
5Fe2(SO4)3 + K2SO4 + 2MnSO4 -f 8H2O, or 316.2 parts by weight
of KMnO4 will oxidize 560 parts by weight of Fe, or 3.727
grammes KMnO4 to the litre will give a solution of about the
strength required.

In the case of bichromate of potassium the reaction is 6FeSO4
+ K2Cr207 + 7H2S04 - 3Fe2(SO4)3 + K2SO4 + Cr2(SO4)3 -f 7H2O,
or 294.5 parts by weight of K2Cr2O7 will oxidize 336 parts of Fe,
or 5-785 grammes of bichromate of potassium dissolved in I
litre of water will give a solution 100 c.c. of which will be
equivalent to about .66 gramme Fe.

To prepare the solutions, therefore, dissolve the above weights,
or multiples of them, in pure distilled water, allow the solution
to stand for some little time, filter through asbestos, and dilute to
the proper volume. Mix thoroughly by shaking in the bottle,

* See page 55.

f See page 56.

DETERMINATION OF FERROUS OXIDE.

and standardize as above directed. The solutions should be kept
in glass-stoppered bottles in a dark closet, and the bottles should
be well shaken whenever the solution is used.

DETERMINATION OF IRON EXISTING AS FeO.

Many iron ores contain iron in the state of FeO, and this
FeO may be either soluble or insoluble in HC1. To determine FeO soluble
the FeO soluble in HC1, weigh I gramme of the finely-ground
ore into the flask A, Fig. 91, of about 100 c.c. capacity. Close
the flask with a rubber stopper fitted with the two glass tubes B
and C, and place it in the position shown in the sketch. Connect
the tube C by means of a piece of rubber tubing with the bent
tube D dipping below the surface of the water in the beaker E.
Pass a current of CO2 through the tube B until all the air is
expelled, then remove for a moment the rubber tube connecting
B with the source of CO2, and by means of a small funnel and
rubber connector introduce into the flask A, through B, 10-12
c.c. strong HC1, and establish the current of CO2 as before. Heat
the flask carefully, and when the ore is entirely decomposed, or
the HC1 ceases to exert any further action on it, remove the source
of heat, stop the current of CO2 for a moment, cool the flask with
the hand, and allow the partial vacuum thus formed to draw the
water from E back into A. Turn on the current of CO2 again,
place a dish of cold water under the flask A, and allow the solu-
tion to cool. Dissolve in a small flask 3 grammes of metallic
zinc in 10 or 15 c.c. H2SO4, diluted with the proper quantity of
water, cool it, and have it ready to pour into the titrating-dish
by the time the solution in the flask A is cool. Wash out the
solution of the ore from the flask A into the dish, add the zinc
solution, dilute to I litre, and titrate with a standard solution.
Subtract from the burette reading the proper correction, calculate
the percentage of Fe, divide by 7, and multiply by 9. The result is

224

ANALYSIS OF IRON ORES.

tion of

the percentage of FeO in the ore soluble in HC1. Allow the solu-
tion in the dish to stand for a few minutes, when all the undecom-
posed particles of ore will settle. Draw off the greater part of

in HC1.

FIG. 91.

the clear supernatant fluid with a siphon, wash the sediment into
a beaker with a jet of cold water, filter on a thin felt* in a Gooch
crucible, and wash the sediment on the felt with cold water.
Transfer the felt and sediment to a platinum crucible, pour into
the crucible 5-10 c.c. HC1 and about half the quantity of HF1,

* The asbestos of which the felt is made must be free from FeO.

>».=

DETERMINATION OF FERROUS OXIDE.

cover the crucible, and place it in the water-bath shown in Fig.
92. The crucible rests on a platinum triangle fixed over the hole
in the centre of the tip of the bath. Around this hole is a groove

FIG. 92.

225

j.. o

NCHES

in which a funnel stands as shown in the cut, while the water in
the groove forms a tight joint.* Pass a current of CO2 or coal-
gas through the tube in the side of the bath, as figured in the cut,
to exclude the air, and heat the bath until the residue and felt are
completely dissolved. Wash the crucible out into the titrating-

* Avery, Chem. News, xix. 270; Wilbur and Whittlesay, Crook's Select Methods,
Page 133-

226 ANALYSIS OF IRON ORES.

dish, into which have been poured just previously 3 grammes of
zinc dissolved in H2SO4 and enough cold water to make the solu-
tion up to nearly I litre. Titrate, and calculate the amount of
FeO as before.

Separate Of course separate portions of the ore may be used to deter-

mine the FeO soluble and insoluble in HC1, but it is more trouble-
some, and experience has shown that it is no more accurate, and
soluble in -n some cases less accurate, than the method just described.

Total FeO The total FeO may also be determined in one operation by

operation, treating I gramme of the ore direct in the crucible with 20 c.c.
HC1 and 20 c.c. HF1, but it is often difficult to get the ore perfectly
dissolved even by prolonged heating in the bath, and the ore must
be ground very fine in the agate mortar. It is necessary to re--
move the funnel from time to time, raise the lid of the crucible,
and stir the contents with a platinum wire.

When the ore is completely decomposed by HC1, or when
the portion undecomposed contains no FeO, the treatment of the
residue is unnecessary.

When an ore contains much organic matter, an accurate deter-
mination of FeO is often impossible, as the solution of the ore in
HC1 reduces some of the ferric salt.

DETERMINATION OF SULPHUR.

Sulphur exists in two conditions in iron ores, as sulphur in the
form of sulphides and as sulphuric acid in the form of sulphates.
Total sui- To determine the total sulphur, weigh I gramme of the finely-
ground ore into a large platinum crucible, add to it 10 grammes
of Na2CO3 and a little KNO3 (less than I gramme).* Mix

* See pages 46 and 48. It is well to make a blank determination, using the
same amounts of Na2CO3, KNO3, and HC1, applying the amount of BaSO4 found
as a correction.

DE1ERMINATION OF SULPHUR.

22/

thoroughly with a platinum wire, and heat carefully over a large
Bunsen burner or blast-lamp until the mass appears perfectly
liquid and in a tranquil state of fusion. Run the fusion well up
on the sides of the crucible, allow it to cool, and treat it in the
crucible with boiling water. Pour the liquid into a tall, narrow
beaker, treat the crucible again with boiling water, and repeat the
operation until all the sodium salts are dissolved and nothing
remains in the crucible except the unavoidable stains. Stir the
liquid in the beaker well, and allow the oxide of iron to settle. If
the solution is colored red or green, it is proof of the presence Evidence or
of manganese in the ore ; add a few drops of alcohol, which will ™e*"gand
precipitate the manganese as oxide, leaving the solution colorless
unless the ore contains chromium, in which case the solution will
be yellowish. Decant the supernatant liquid on a small filter,
allowing the filtrate to run into a No. 4 beaker, fill the small beaker
nearly full of hot water, stir well, and allow to settle. Decant again
on the filter, and repeat the operation once more. Acidulate the
collected filtrates with HC1 (about 20 c.c. will be required), evapo-
rate to dryness in the air-bath, redissolve in water with a few drops
of HC1, filter into a No. 3 beaker, heat the filtrate to boiling, and
add 10 c.c. of a solution of chloride of barium.* Allow to stand
for some hours, filter on the Gooch crucible or on a small ashless
filter, ignite, and weigh as BaSO4, which multiplied by .1376 gives
the weight of S. The insoluble portion from the aqueous solu-
tion of the fusion may be used to determine the total iron in the
ore, and is very convenient for this purpose in ores difficult to
dissolve. Pour into the crucible in which the fusion was made
about 10 c.c. HC1, place the lid on the crucible, and warm the
crucible slightly to dissolve the adhering oxides, dilute with
about an equal bulk of water, and pour it on the small filter
through which the aqueous solution was decanted, allowing it to
run into the beaker which contains the residue of oxide of iron,

iron in the

fusion'

* See page 51.

228 ANALYSIS OF IRON ORES.

etc. Wash out the crucible, pouring the washings on the filter,
and wash the filter free from iron with a jet of cold water. Evap-
orate the solution in the beaker to dryness, redissolve in 10 c.c.
HC1, and transfer the solution of ferric chloride, the silica, etc.,
to one of the small flasks, deoxidize, and titrate as directed.

The sulphur which exists as sulphuric acid in an iron ore
is usually combined with either calcium or barium : as sulphate
of calcium or of any of the other alkaline earths except barium,
of the alkalies, or of the metals, it is soluble in HC1 ; as sulphate
of barium it is practically insoluble. We may, therefore, deter-

Determi- mine the soluble sulphates as follows : Boil 10 grammes of the
soiubie° ore with 30 c.c. HC1 and 60 c.c. water, filter from the mass of the
sulphates. uncjjssoivecj ore> evaporate the filtrate to dryness, redissolve in
HC1 and water (1—2), filter into a No. 2 beaker, nearly neutral-
ize by NH4HO, heat to boiling, and precipitate by BaCl2 solu-
tion. Filter and wash the precipitate, ignite, and weigh as
BaSO4, which contains 34.352 per cent. SO3.

Determi- To determine the sulphuric acid which exists as sulphate of

sulphate barium, treat 10 grammes of the ore with 50 c.c. HC1 until the
um' ore appears to be decomposed. Evaporate to dryness, redis-
solve in dilute HC1 (1-3), dilute, filter, and wash the insoluble
matter thoroughly. Ignite and fuse the insoluble matter with
Na2CO3, treat the fused mass with hot water, and filter. In
the filtrate is the sulphuric acid as sulphate of sodium, while
the barium remains on the filter as carbonate of barium. It is
safer to calculate the sulphate of barium from the amount of
barium rather than from the amount of sulphuric acid, as the
ore may contain sulphides (pyrites, etc.), which are not decom-
posed by HC1, but are decomposed and partly oxidized by fusion
with Na2CO3. The other forms of barium besides the sulphate
(silicate and carbonate) are readily decomposed by HC1, and
are not likely to be found with the barium in the insoluble
residue. It is, of course, possible to suppose the coexistence
of silicate or carbonate of barium and of sulphate of calcium

DETERMINATION OF PHOSPHORIC ACID.

in an ore, and the consequent formation of sulphate of barium
when the ore is decomposed by HC1; but, as the soluble sul-
phuric acid is determined in one operation and the insoluble
in another,* the total amount of sulphuric acid existing as such
is determined, and the object of the analysis attained. To deter-
mine the barium, then, treat the insoluble matter obtained by
the filtration of the aqueous solution of the fusion by dilute
HC1, evaporate to dryness to render SiO2 insoluble, redissolve
in water with a few drops of HC1, filter into a No. 2 beaker,
heat the filtrate to boiling, and add a few drops of H2SO4
diluted with a little water. Allow the precipitate to settle, filter,
wash, ignite, and weigh as BaSO4, from which weight calculate
the amount of SO3 in the ore insoluble in HC1. To find the
amount of sulphur existing as sulphides, subtract from the total
S the amount of S in the SO3 found as sulphates.

DETERMINATION OF PHOSPHORIC ACID.

Treat 5 or IQ grammes of the finely-ground ore in 30 or solution of
60 c.c. HC1. (With low phosphorus ores use 10 grammes ; with
others, 5 grammes.) When the ore is decomposed, evaporate
to dryness, redissolve in 20 or 40 c.c. HC1, dilute, filter, and
proceed exactly as directed in the determination of phosphorus
in iron and steel, page 81 et seq. The weight of the Mg2P2O7
multiplied by .63788 gives the weight of the P2O5. The weight
of the phospho-molybdate of ammonium multiplied by .03735
gives the weight of the P2O5.

Titanic acid is very generally found associated with iron Precautions
ores, and may be regarded as one of the usual constituents.

* The insoluble matter from the treatment of 10 grammes of the ore with HC1
for the determination of soluble sulphates, page 228, may be used to determine the
sulphate of barium.

230

ANALYSIS OF IRON ORES.

Means of
recogniz-
ing titan-
iferous
ores.

Ores con-
taining
barium.

Additional
test for
titanic
acid.

As mentioned on page 86 its presence, if overlooked, may lead
to serious errors in the determination of phosphoric acid. When
an ore contains much titanic acid it may readily be recognized
by the peculiar milky appearance of the solution when it is
diluted preparatory to filtering off the insoluble matter, and by
the strong tendency it shows to run through the filter as soon
as the attempt is made to wash the insoluble matter with water.
Smaller quantities of titanic acid may be recognized by the
clouding of the solution when it is deoxidized by bisulphite of
ammonium, as noted on page 89. In the latter case, however,
this clouding may be caused by the formation of sulphate of
barium when the ore contains the latter element in the form
of carbonate or silicate. Silica in the solution may also cause
a cloud under those circumstances which closely resembles that
caused by titanic acid, while sulphate of barium may readily
be distinguished from either by its granular appearance and its
tendency to settle to the bottom of the beaker.

The insoluble residue from the solution of the ore in HC1
should, therefore, be treated to recover any P2O5 which may
have remained insoluble in combination with TiO2<* An ad-
ditional test for the presence of titanic acid, and one that rarely
fails even with very small amounts, is to dissolve the insoluble
matter from the aqueous solution of the fusion of the residue
from the HF1 and H2SO4 treatment of the insoluble residue
from the ore, in dilute HC1, allowing it to run into a test-tube
and adding metallic zinc. When titanic acid is present the solu-
tion becomes first colorless, and then pink or purple, and finally
blue from the formation of Ti2O3. The simplest way is to pro-

* When HF1 is not available, fuse the residue with Na2CO3, treat the fused
mass with hot water, filter, acidulate the filtrate with HC1, evaporate to clryness to
render SiO2 insoluble. Redissolve in water with a little HC1, filter, and add the
filtrate to the main solution, or add a little Fe2Cl6, and make a separate acetate
precipitation in this portion, adding the solution to the solution of the main acetate
precipitation.

DETERMINATION OF TITANIC ACID. 231

ceed as directed an pages 88 and 89 when using the acetate
method, or on page 94 when using the molybdate method.
These methods are not practicable, however, when the ore
contains a very large amount of TiO2, and recourse must be
had to the method described on page 86 et seq., involving the
fusion of the acetate precipitate and the residue from the treat- Fusion of
ment of the insoluble matter with HF1 and H2SO4, with

and a little NaNO3. It is best to pursue this method at any
rate whenever TiO2 is also to be determined, as the same por-
tion can be used for the estimation of both TiO2 and P2O5, and
the aggregate labor involved is much lessened.

DETERMINATION OF TITANIC ACID.

The determination of titanic acid has always presented many Difficulties
difficulties, and its separation from a large amount of oxide of CiPitation
iron and alumina has been far from satisfactory, besides being
most tedious. The principal sources of error in the estimation
of titanic acid in iron ores are the tendency of P2O5 to prevent the
precipitation of TiO2 by boiling, when its sulphuric acid solution
contains P2O5 and ferrous sulphate, and the liability of A12O3 to
separate out with the TiO2 when the latter is precipitated under
the circumstances above mentioned. There is also a mechanical
difficulty, caused by the adhesion of the precipitated TiO2 to the
bottom and sides of the beaker, from which it can sometimes be
removed only by boiling with a strong solution of caustic potassa.
The admirable series of experiments carried out by Dr. Gooch *
on the separation of aluminium and titanium suggests a method
which renders the determination of TiO2 in iron ores much less
troublesome, while adding greatly to the accuracy of the results.

* Proceedings Am. Acad. Arts and Sciences, New Series, vol. xii. p. 435.

232

ANAL YSIS OF IRON ORES.

Details
of the

method.

Principles
involved.

In carrying out the details of the method, dissolve 5 or 10
grammes of the ore in HC1, and proceed exactly as in the deter-
mination of P2O5, by fusing the residue from the treatment of
the insoluble matter by HF1 and H2SO4 and the acetate pre-
cipitate with Na2CO3 and a little NaNO3,* and then complete
the operation exactly as described in the determination of Ti in
pig-iron.f

The essential points in this method are — i. Separation of the
TiO2 from the mass of Fe2O3 by acetate of ammonium in the
deoxidized solution. 2. Separation from all the P2O5 and the
greater part of the A12O3 by fusion with Na2CO3, by which means
a titanate -of sodium insoluble in water is formed, and at the same
time phosphate and aluminate of sodium soluble in that men-
struum. 3. Separation from the last traces of A12O3 from the iron,
calcium, etc., by precipitating the TiO2 in the thoroughly deoxi-
dized solution in the presence of a large excess of acetic acid and
some SO2, the sulphuric acid being all in the form of sulphate
of sodium. The addition of a large excess of acetate of sodium,
by which this latter condition is effected, converts all the sulphates
of iron, calcium, etc., into acetates, and precipitates the TiO2
almost instantaneously as a hydrate, which is flocculent, settles
quickly, shows no tendency to run through the filter, and is
washed with the greatest ease. It sometimes happens that a little
FeO is precipitated with the TiO2, and the latter, after ignition,
appears discolored; in this case fuse with a little Na2CO3, add
H2SO4 to the cold fused mass, dissolve, and repeat the precipita-
tion with acetate of sodium in the presence of sulphurous and
acetic acids exactly as in the first instance.

A number of experiments covering all the points involved in
this method show it to be extremely accurate and entirely trust-
worthy.

* See page 86 et seq.

f See page 178 et seq.

DETERMINATION OF MANGANESE. 333

DETERMINATION OF MANGANESE.

When manganese alone is to be determined in an ore, any
one of the methods described under the determination of manga-
nese in iron and steel, page 109 et seq., may be used. The most
convenient, however, is Ford's method with the modifications Ford>s

- f method.

necessary in the analysis of pig-iron, page 117. The only change
requisite is to evaporate the solution in HC1 to dryness to render
silica insoluble before filtering off the insoluble matter.

In the determination of manganese in high grade manganese
ores, it is best to use a one-tenth factor weight (0.3874 gramme)
of the sample, dissolve in hydrochloric acid, evaporate to dryness,
redissolve in dilute hydrochloric acid and filter off the insoluble
matter. Ignite the insoluble matter in a platinum crucible, fuse
with a little sodium carbonate, dissolve in water, acidulate with
hydrochloric acid, and evaporate to dryness. Redissolve in dilute
hydrochloric acid and filter into the main solution. Or, treat the
ignited insoluble matter with sulphuric and hydrofluoric acids,
drive off the hydrofluoric and the excess of sulphuric, cool, add
water and a little hydrochloric acid, and heat until the residue
dissolves, then add the solution to the main solution of the ore.

Evaporate the main solution until it is syrupy, add an excess
of strong nitric acid and evaporate off the hydrochloric acid.
Precipitate by potassium chlorate in the usual way and filter
through asbestos. Wash the precipitate thoroughly with cold
water to get rid of the calcium nitrate, which, being practically
insoluble in strong nitric acid, will remain with the precipitated
manganese dioxide, unless this precaution be observed. There is
no danger of dissolving the manganese dioxide by this treatment.

Proceed with the determination as directed on page 116.
Each milligramme of manganese pyrophosphate is a tenth of one
per cent, of manganese in the ore.

In using the acetate method it is, of course, necessary that The acetate
all the iron should be in the form of Fe2Cl6, and also that there method'
should be no oxidizing agent in the solution. Even a very small

234

ANALYSIS OF IRON ORES.

amount of FeCl2 will cause the formation of a " brick-dust" precipi-
tate, which cannot be kept from passing the filter while some of
the iron remains dissolved in the acetate solution. When, there-
fore, the ore contains FeO, it should be oxidized by HNO3 or
KC1O3, and the excess of the oxidizing agent removed by evapo-
ration with HC1.

Volhard's Method Applied to High Grade Manganese Ores.

Volhard's is the most satisfactory volumetric method for high
grade manganese ores. Dissolve I gramme of the ore in a small
beaker in hydrochloric acid, heat until the chlorine is all driven
off, wash out into a platinum dish (Fig. 36), and add 5 c.c. strong
sulphuric acid and a little hydrofluoric acid. Evaporate to dry-
ness and heat until the sulphuric acid begins to volatilize. Cool,
dissolve in water, transfer to a 300 c.c. flask, and proceed as
directed on page 116, except that 100 c.c. of the filtered solution
representing one-third of a gramme of the ore is used.

In running in the permanganate it is necessary to heat the
solution in the flask after there appears to be a slight excess.
This will make the precipitate settle rapidly and generally show
the necessity for adding more permanganate.

A large number of comparative analyses have shown that it
is necessary to add one one-hundredth of the amount obtained to
get the true percentage of manganese ; in other words, the results
obtained are always one one-hundredth too low.

For instance, if by calculation the ore contains 50 per cent,
of manganese by this method, the true result is 50.5 per cent.

Pattinson's Method.1

Dissolve in hydrochloric acid such a quantity of the sample
as shall contain not more than 0.25 gramme of manganese. In
high manganese ores add enough ferric chloride to the solution
to make the iron and manganese contents about equal. Add

1 Society of Chemical Industry, vol. x. No. 4.

DETERMINATION OF MANGANESE.

235

calcium carbonate to the solution until it is slightly red in color
and acidulate by adding hydrochloric acid until the red color
disappears. Add sufficient zinc chloride in solution to give 0.5
gramme metallic zinc. Heat to boiling and dilute with boiling
water to 300 c.c., and add 60 c.c. of a solution of calcium hypo-
chlorite containing 33 grammes to the litre. To the solution of
hypochlorite just before using it, add enough hydrochloric acid to
give it a faint greenish tinge after agitation.

Finally add 3 grammes of calcium carbonate diffused in 1 5 c.c.
of boiling water, and after stirring well 2 c.c. of methyl alcohol.

Filter on a large filter and wash with water at 65° until a strip
of iodized starch paper gives no indication of chlorine.

Measure into a beaker 100 c.c. of a carefully standardized
strongly acid solution of ferrous sulphate containing 10 grammes
of iron to the litre and place the precipitate and filter in it. When
the precipitate has dissolved add cold water and determine the
excess of ferrous sulphate by a standard solution of potassium
bichromate.

When the ore contains much organic matter it should be fil- FCO and
tered off before attempting to oxidize the ferrous salt, as it is quite mftterta
impossible in some cases to destroy the organic matter, and reso-
lution of the evaporated mass in HC1 causes a reduction of some
of the ferric salt.

Many manganiferous iron ores contain manganese in a higher Ores con-
state of oxidation than the protoxide, and the determination of the
excess of oxygen is often necessary. All ores of this character
when treated with HC1 evolve chlorine gas, which, is easily recog-
nized by its yellowish-green color and peculiarly irritating odor.
The reaction by which chlorine is liberated is MnO2 + 4HCl =
MnCl2 -f- 2H2O -j- 2C1, or each molecule of MnO2 = 87 corresponds
to 2 molecules of Cl = 70.90. This reaction is the basis of Bun-
sen's method for the estimation of the amount of the MnO2 in
manganese ores, which consists in driving the liberated Cl into a
solution of iodide of potassium, and determining the amount of

236

Bunsen's
method.

ANALYSIS OF IRON ORES.

iodine set free, by starch and hyposulphite solution. When the
method given on page 68 et seq. for determining sulphur in steel
is in use, the solutions employed in carrying out that method
(with the exception of the iodine in iodide of potassium) can be
used in this, or they may be prepared by the directions there
given, for use in this method.

Weigh from .5 gramme to I gramme of the finely-ground ore
into the flask a, Fig. 93, pour in 10 c.c. strong HC1, connect the

FIG. 93.

bent tube b quickly by means of a piece of gum tubing, and heat
the flask gently at first and finally to boiling to drive all the Cl
over into the tube r, which contains a strong solution of pure
iodide of potassium free from iodate. This tube is placed in ice-
water. When all the Cl has been expelled from the flask a and
absorbed in c, detach the latter, wash its contents into a large dish,

DETERMINATION OF MANGANESE.

237

add a little starch solution, and run in the hyposulphite until the
blue color just vanishes. If, as in the example given on page 70, Example.
I c.c. of the hyposulphite solution is equal to .01267 gramme of
iodine, and I equivalent of chlorine =3 5. 45 replaces i equiva-
lent of iodine = 126.85 in the iodide of potassium, i c.c. of the
hyposulphite solution would be equal to (126.85 : 35.45 :: .01267:
.003541) .003541 gramme of chlorine; and, as I equivalent of
MnO2 = 87 is equal to 2 equivalents of chlorine = 70.90, i c.c. of
the hyposulphite would be equal to (70.90 : 87 : : .003541 : .004345)
.004345 grammes MnO2.

In most laboratories, however, it is generally more convenient
to determine the amount of MnO2 in an ore by determining its oxi-
dizing power on a solution of ferrous salt. The reaction is 2FeSO4
+ MnO2 + 2H2SO4 = Fe2(SO4)3 + MnSO4 + 2H2O, or 2 equivalents
of Fe = 1 12 are equal to i equivalent of MnO2 = 87. Grind in an

tion by

agate or Wedgwood mortar about 10 or 15 grammes of ferrous means of
sulphate or ammonio-ferrous sulphate, and weigh out two portions, Su7phate.
one of 2 grammes and one of 3 to 8 grammes, according to the
quality of the manganese ore. One gramme of pure MnO2 would
oxidize 1.2874 grammes of Fe, equal to nearly 6.5 grammes of
ferrous sulphate, -or more than 9 grammes of ammonio-ferrous
sulphate. Transfer the 2-gramme portion to the dish, add a large
amount of water and about 5 c.c. HC1, and pour in 3 grammes of
zinc dissolved in 10 c.c. H2SO4 diluted with enough water to dis-
solve the sulphate of zinc readily. Titrate with the standard solu-
tion of permanganate or bichromate of potassium in the usual way,
and calculate the amount of iron in i gramme of the ferrous salt
used. Weigh into the flask A, Fig. 90, page 218, I gramme of the
finely-ground ore, and add to it the larger portion of the ferrous
salt previously weighed out. Connect the flask as in Fig. 91, and
pass in a current of CO2 until the air has been driven out. Now
pour into the flask A, by means of a small funnel attached to B,
10 c.c. HC1 and 30 c.c. water, reconnect the CO2 apparatus, and
while the current of CO2 is passing dissolve the ore, heating the

238 ANALYSIS OF IRON ORES.

flask, and shaking it from time to time as necessary. When the
ore is all decomposed, stop the current of CO2 for a moment,
remove the light, and allow the water in E to flow back into the
flask A. Transfer the solution to the dish, add 3 grammes zinc
dissolved in H2SO4, and titrate it with the standard solution.
From the titration of the ferrous salt calculate the amount of
Fe in the amount used in the solution of the ore, and subtract
from this the amount found by this last titration ; the difference
is the weight of Fe oxidized by the chlorine liberated from
the MnO2 in the ore. Then, as 112 parts of Fe correspond to
87 parts of MnO2, multiply the above weight of iron by 87
and divide by 112, and the result is the weight of MnO2 in
the ore.
Calculation The total Mn having been determined by one of the methods

of MnO

and previously given, subtract from it the amount of Mn as MnO2

(found by multiplying the weight of MnO2 by .63218), and cal-
culate the difference to MnO by multiplying by 1.2909.

DETERMINATION OF SILICA, ALUMINA, LIME,
MAGNESIA, OXIDE OF MANGANESE, AND
BARYTA.

Treatment of iron ores with HC1 leaves a residue which only
residue in very rare instances consists of silica alone, being usually sili-
cates of aluminium, calcium, and magnesium, mixed with an
excess of silica. These silicates are often much more complicated,
and contain, besides the substances enumerated above, protoxide
of iron, soda, potassa, and oxide of manganese. With these sili-
cates are occasionally found titanic acid, titaniferous iron, chrome
iron ore, sulphate of barium, and ferrous sulphide, besides organic
matter, and sometimes graphite. As this residue must be fused
with Na2CO3 in order to decompose it, and the introduction of

DETERMINATION OF SILICA, ALUMINA, ETC. 239

sodium salts into the main solution is not desirable, the two por-
tions of the ore (the soluble and the insoluble in HC1) should be
analyzed separately.

Weigh i gramme of ore into a No. I beaker, add 15 c.c. HC1,
cover with a watch-glass, and digest at a gentle heat until the ore
appears to be quite decomposed, add a few drops of HNO3, heat
until the action has ceased, and then wash off the cover with a
fine jet of water, and evaporate to dryness. Redissolve in HC1,
and evaporate to dryness a second time to render all the silica
insoluble. Redissolve in 10 c.c. HC1 and 30 c.c. water, filter, solution of
transfer all the residue to the filter (a small ashless filter) with a
fine jet of cold water, using a "policeman" to detach any ad-
hering particles from the beaker, and wash the filter with a little
HC1 and plenty of cold water. Allow the filtrate and washings
to run into a No. 5 beaker, and ignite and weigh the residue as
"Insoluble Silicious Matter"

Add to the insoluble matter in the crucible about ten times its Analysis
weight of pure dry Na2CO3 and fuse it. Run the fusion well up

on the sides of the crucible and treat it with hot water. Wash it silicious

matter.

out into a platinum dish, dissolve any particles adhering to the
crucible in HC1, and add this to the solution in the dish. Acidu-
late with HC1, evaporate to dryness, moisten with HC1 and water,
evaporate to dryness a second time to render silica insoluble, then
pour into the dish 5 c.c. HC1 and 15 c.c. water, and stand it in a
warm place for some time. Dilute with about 20 c.c. water, filter
on a small ashless filter, wash well with hot water, receiving the
filtrate and washings in a small beaker, dry, ignite, and weigh.
Treat the ignited precipitate with HF1 and a drop or two of
H2SO4, evaporate to dryness, ignite, and weigh again. The differ- SiOa<
ence between the two weights is SiO2. If the difference between
the last weight and the weight of the empty crucible is more than
a milligramme or two, the residue must be examined and its nature

determined. This residue may consist of titanic acid, sulphate of from HFl

and H2S04

barium, alumina, or sulphate of sodium (from imperfect washing treatment

240

ANALYSIS OF IRON ORES.

of the silica). If it is titanic acid or alumina, the weight must be

added to the weights of the A12O3, etc.

Return the filtrate from the SiO2 to the dish in which it was

previously contained, heat to boiling, add a few drops of bromine-
Ai2o3, etc. water and an excess of NH4HO, boil until it smells but faintly

of NH3, filter on a small ashless filter, wash well with hot
Possible water, dry, ignite, and weigh as A12O3, etc. Besides alumina

constit-
uents of this precipitate may contain titanic acid, sesquioxide of chro-

dpStatT mium, sesquioxide of iron, oxide of manganese, and phosphoric
acid.

Return the filtrate from this precipitate to the dish, evaporate
down to about 100 c.c., add oxalate of ammonium and ammonia,
boil for a few minutes, allow the precipitate to settle, filter on
a small ashless filter, ignite finally for five minutes over a blast-
Cao. lamp, and weigh as CaO. To the filtrate from the oxalate of

calcium add microcosmic salt and about one-third the volume
of the solution of ammonia, cool in ice-water, stir vigorously
several times, and allow to stand overnight so that the precipi-
tated Mg2(NH4)2P2O8 may settle properly, filter, wash with water
containing one-third its volume of ammonia and about 100
grammes of nitrate of ammonium to the litre, ignite carefully,
and weigh. Dissolve the precipitate in the crucible in a little
water containing from 5 to 10 drops HC1, filter through a small
MgO. ashless filter, which dry, ignite, and weigh. The difference

between the two weights is Mg2P2O7, which, multiplied by
.36212, gives the weight of MgO.

Analysis of When barium has been shown to exist in the ore, as noted

from the on page 222, heat the filtrate from the Insoluble Silicious Matter

^lidous" to boiling, add a few drops of H2SO4, boil for a few minutes

Matter- to allow the precipitate to settle, filter on a small ashless filter,

Bao. allowing the filtrate and washings to run into a No. 5 beaker,

dry, ignite, and weigh as BaSO4, which, multiplied by .65648,

gives the weight of BaO.

To the cold filtrate from the BaSO4 add NH4HO until the solu-

DETERMINATION OF SILICA, ALUMINA, ETC. 24!

tion is nearly neutralized, then add a solution of carbonate of am-

lion by

monium until a slight permanent precipitate is formed which fails acetate
to dissolve after vigorous stirring, and redissolve this by the care-
ful addition of HC1, drop by drop, stirring well, and allowing the
solution to stand for a short time after each addition of HC1. As
soon as the solution clears, add a solution of acetate of ammo-
nium, made by slightly acidulating 5 c.c. of NH4HO by acetic
acid, dilute to about 600 c.c. with boiling water, and boil for a
few minutes. Allow the precipitate to settle, decant the clear
liquid through a large washed German filter, pour the precipitate
on the filter, and wash it two or three times with boiling water.
With the aid of a platinum spatula return the precipitate to the
beaker in which the precipitation was made, dissolving any portion
remaining on the filter or adhering to the spatula in dilute HC1,
allowing the acid to run into the beaker containing the precipitate.
Wash the filter thoroughly with cold water, and evaporate the
solution and washings to dryness. Redissolve in dilute HC1,
filter into a large platinum dish, dilute with hot water,* heat to
boiling, and add a slight excess of ammonia. Boil for a few
minutes to make the precipitate granular and expel the excess of
ammonia, and filter on an ashless filter (using the filter-pump
and cone, page 26, with very slight pressure, if practicable. Dis-
solve any of the adhering particles of the precipitate in the dish
in a very few drops of HC1, heating the bottom of the dish
slightly, wash off the rod and cover, and wash down the sides
of the dish with hot water, add a slight excess of ammonia, heat
gently until the precipitate of ferric hydrate separates, wash this

* The distilled water used in the complete analysis of iron ores should never be
heated in glass vessels for any length of time, as glass is sensibly attacked by it. An
experiment in which distilled water free from residue was heated for twelve hours in
a Bohemian flask showed that the water dissolved 52 milligrammes of solid matter
to the litre, of which 26 milligrammes were SiO2. The water should always be heated
in platinum or porcelain dishes, or in tin-lined copper flasks. For convenience, the
water may be poured into the washing-flasks for immediate use.

242 ANALYSIS OF IRON ORES.

on the filter, and wash the precipitate thoroughly with hot water.
Dry the filter and precipitate carefully, transfer the latter to a
weighed crucible, burn the filter in a wire, add the ash to the
precipitate, and heat the crucible, keeping it carefully covered,
and raising the heat very gradually and slowly to expel the last
traces of moisture from the precipitate of ferric hydrate. Finally
heat the crucible to bright redness, and then to the highest tem-
perature of the blast-lamp for about five to ten minutes. Cool,
Fe2o3+ ignite, and weigh as Fe2O3 + A12O3 + P2O5 ( + TiO2 + Cr2O3 +

A12O3 +

p2o6. As2O5).

Add the filtrate and washings from the acetate precipitation to
those from the precipitation by ammonia, evaporate down to about
200 c.c. in a platinum dish, filter off any slight precipitate of Fe2O3
(which must be ignited, weighed, and the weight added to that of
the Fe2O3, etc.), add 20 to 30 drops of acetic acid, heat to boil-
ing, and pass a current of H2S through the solution for fifteen
or twenty minutes, keeping the solution hot during the passage
of the gas. Filter off the precipitated sulphides of copper, zinc,
nickel, and cobalt, wash with H2S water containing a little free
acetic acid, and to the filtrate add excess of ammonia and sul-
phide of ammonium. Allow the precipitated sulphide of man-
ganese to settle, decant the clear, supernatant liquid through a
filter, but before pouring the precipitate on the filter remove the
beaker containing the filtrate and substitute a clean beaker, for
the precipitate is almost certain at first to run through the filter.
Wash the precipitate and filter with water containing a little sul-
phide of ammonium, add the clear filtrate and washings together,
and stand them aside. Dissolve the precipitate of sulphide of
manganese on the filter in dilute HC1, and wash the filter thor-
oughly with hot water, receiving the solution and washings in a
small beaker. Heat to boiling to expel H2S, and, when the excess
is driven off, destroy the last traces with a little bromine-water,
transfer the solution to a platinum dish, and precipitate by micro-
cosmic salt and ammonia as directed on page 112. Filter, wash,

DETERMINATION OF SILICA, ALUMINA, ETC.

243

ignite, and weigh as Mn2P2O7, which, multiplied by .50011, gives
the weight of MnO. Mno.

Acidulate the filtrate from the sulphide of manganese with
HC1, boil off all the H2S, filter from the sulphur deposited by this
operation into a platinum dish, add an excess of ammonia and
oxalate of ammonium, filter off, ignite, and heat at the highest
temperature of the blast-lamp for fifteen minutes, cool, and weigh
as CaO. Cao.

Precipitate the magnesia in the filtrate as directed on page 232,
and determine the weight of Mg2P2O7, which, multiplied by .36212,
gives the weight of MgO. Mgo.

By adding the elements determined in the insoluble portion to
the similar ones in the soluble portion, we get the total amounts
of each in the ore. Thus, we have from the above analysis

Si02,Fe203 + Al203+P205+Cr203 + Ti02 + As205, MnO, CaO,
and MgO, and it becomes, of course, necessary to calculate prop-
erly the iron in its different states of oxidation and to determine
the amount of A12O3 in the ore. It is much more accurate to
determine in separate portions of the ore the amounts of P2O5,
As2O5, Cr2O3, Fe2O3, and TiO2 than to attempt to make the sepa-
ration in the precipitate obtained in this portion. Therefore,
knowing the amounts of these substances, the Fe2O3 from the vol-
umetric determination of iron, as previously described, and the
amount of each of the others as found by one of the methods
given, add together the weights of the Fe2O3, the P2O5, the Cr2O3,
the TiO2, and the As2O5 in one gramme of the ore, and subtract
the sum from the weight of the precipitate obtained in the above
analysis, the result is the weight of A12O3 in one gramme of the Ai2o3.
ore.

Iron may exist in an ore in several conditions, as Fe-jO^ as
FeO, as FeS2, as FeAs2, etc. While it may not always be possible
to determine the exact conditions in which it exists, the rule
usually followed is, after subtracting from the sulphur existing
as sulphides (page 229) the amount necessary to form sulphide

244

ANALYSIS OF IRON ORES.

Fes2.

Feo.

Method for
ores con-

taining

of copper, sulphide of nickel, etc., to calculate the remainder as
FeS2 by multiplying the weight of S by 1.87336. The weight of
S subtracted from this gives the weight of iron in the FeS2. Now
from the weight of FeAs2 subtract the weight of arsenic, and
the result is the weight of iron existing as Fe in the FeAs2.*
Add the Fe in the FeS2 to the Fe in the FeAs2, and subtract
this weight from the Fe found as FeO, the remainder calculated
to FeO is the amount of FeO in the ore. Subtract the total
amount of Fe found originally by titration to exist as FeO from
the total Fe found in the ore, and calculate the remainder to
Fe2O3.

When an iron ore contains only a very small amount of man-
ganese, the acetate separation may be omitted in the method as
given above, which simplifies and shortens the operation very
materially. In this event transfer the filtrate from the insoluble
silicious matter at once to a large platinum dish, heat to boiling,
add a few c.c. of bromine-water and then excess of ammonia, boil,
and filter the Fe2O3, etc., on an ashless filter, dry, ignite, and
weigh, as described above. The manganese will be in the pre-
cipitate after ignition as Mn3O4, and the amount calculated from
the determination of manganese made in a separate portion of the
ore must be subtracted from the weight of the above precipitate
in calculating the amount of A12O3.

The lime and magnesia are determined in the filtrate from the
Fe2O3, etc., providing, of course, that the ore contains only minute
amounts of nickel, copper, etc.

The same general method described above is applicable when
the ore contains quite a large amount of titanic acid, so much,
in fact, as to cause the cloudiness in the filtrate from the insolu-
ble silicious matter, as noted on page 230. Whenever an acetate
separation is necessary in an ore of this character, the precipitate
must be filtered on an ashless filter, and this filter, as well as the

All the weights, of course, are calculated to i gramme of ore.

TITANIFEROUS ORES.

245

filter containing any insoluble matter from the resolution of the
acetate precipitate, must be ignited and examined for TiO2 by
treating the residue with HF1 and H2SO4, heating to redness,
fusing with Na2CO3, dissolving in HC1 and water, and precipi-
tating by ammonia. The precipitate so obtained is to be filtered,
ignited, and the weight added to that of the Fe2O3, etc. Ilmenite
even, when very finely ground in an agate mortar, is frequently
capable of being almost entirely decomposed by HC1, and when
this is the case it is of advantage to use this method of analysis.
It may be necessary, however, under certain circumstances to
decompose the ore at the start by fusing with bisulphate of potas-
sium. To carry out this method, weigh I gramme of the ore, Fusion with
which has been ground as fine as possible in an agate mortar, into of^aL*
a large platinum crucible, add 10 grammes of pure bisulphate of
potassium,* and heat the crucible, carefully covered, over a very
low light until the bisulphate is melted. It is necessary to watch
this operation most carefully, for the bisulphate has a strong
tendency to boil over, and only unremitting attention on the part
of the analyst will prevent the loss of the analysis. It is well at
the start to stand by the crucible and raise the lid slightly at very Precautions
short intervals to watch the condition and progress of the fusion.
The lid should be held just over the crucible and in a horizontal
position, otherwise the particles which have spirted on it from the
mass in the crucible may run to the edge of the lid and, when the
latter is replaced, down the outside of the crucible. Raise the
heat very gradually, keeping the mass just liquid and the tem-
perature at the point at which slight fumes of SO3 are given off
when the lid is raised, until the bottom of the crucible is dull red.
When the ore is completely decomposed, remove the light, take
off the lid of the crucible, and incline the latter at such an angle
that the fused mass may run together on one side of the crucible
and as near the top as possible. Allow it to cool in this position ;

* See page 49. •

246

ANALYSIS OF IRON ORES.

Solution of
the fused
mass.

SiO2.

Treatment
of impure
precipitate
of TiO2.

TiO2.

Fe2O3 and
A12O3 car-
ried down
with first
precipitate
of Ti02.

when cold it is easily detached from the crucible. Place the
crucible and lid in a No. 4 beaker half full of cold water, and the
fused mass in the little basket, as shown in Fig. 76, page 165.
Pour into the beaker enough strong aqueous solution of sulphur-
ous acid to raise the liquid to the top of the basket, and allow
the fusion to dissolve, which may require twelve hours. Wash off
with a jet of cold water, and remove the basket, the crucible, and
lid, stir the liquid, which should smell strongly of SO2, and allow
the insoluble matter to settle. Filter on an ashless filter, wash
well with cold water, dry, ignite, and weigh. Treat with HF1 and
2 or 3 drops of H2SO4, evaporate to dryness, ignite, and weigh.
The difference between the weights is SiO2. If any appreciable
residue remains in the crucible, fuse with a little Na2CO3, treat
with H2SO4, and add to the main filtrate. To the main filtrate,
which should be quite colorless and which should smell strongly
of SO2, add a clear filtered solution of 20 grammes of acetate of
sodium and one-sixth of its volume of acetic acid, 1.04 sp. gr.,
heat to boiling, and boil for a few minutes. Allow to settle, filter
on an ashless filter, wash thoroughly with hot water containing
one-sixth its volume of acetic acid, and finally with hot water, dry,
ignite, and weigh as TiO2. This precipitate, however, may not be
quite pure, as small amounts of ferric oxide and alumina may be
carried down with it. The best plan to pursue is to fuse with
Na2CO3, dissolve in water, filter, wash, dry, and fuse the insoluble
titanate of sodium, etc., with Na2CO3, treat the cooled mass in the
crucible with H2SO4, and precipitate and determine the TiO2 as
directed above. The two filtrates from the treatment of the first
precipitate of TiO2 may contain a little oxide of iron and alumina.
To recover this, boil down the last filtrate until the greater part of
the sulphurous acid has been driven off, add bromine-water to oxi-
dize the iron, acidulate the aqueous filtrate from the carbonate of
sodium fusion with H2SO4, add it to this solution, boil the united
solutions down in a platinum dish to a convenient volume, and add
a slight excess of ammonia. Boil the solution until it smells

DETERMINATION OF SILICA. 247

faintly but decidedly of ammonia, filter off, and wash slightly.
Redissolve the precipitate in HC1, and reprecipitate by ammonia,
filter, wash, ignite, and weigh as Fe2O3 + A12O3, to be added to the
main precipitate. Boil the main filtrate and washings down in a
large platinum dish after adding enough bromine-water to oxidize
all the iron, add HC1 from time to time when necessary to keep
the iron in solution, and, when reduced to a convenient bulk,
nearly neutralize by ammonia, and boil. Filter off and wash the
precipitate two or three times, redissolve and reprecipitate by
ammonia, filter, wash, dry, ignite, and weigh as Fe2O3 + A12O3 + F^OS*
P2O5. Fuse this precipitate for a long time and at a high tempera- P2o63
ture with Na2CO3, dissolve in water, wash by decantation, redis-
solve the residue of Fe2O3, etc., in HC1, and determine the iron by
titration. Determine the alumina by difference, the P2O5 being
determined in a separate portion. In the filtrate from the Fe2O3 +
A12O3 + P2O5 determine manganese, lime, and magnesia in the MnO.CaO,
usual way.

DETERMINATION OF SILICA.

When silica alone is wanted in an ore a more rapid method is
sometimes desirable. In this case dissolve I gramme of the ore in
HC1, evaporate to dryness, redissolve in dilute HC1, filter on an
ashless filter, wash, dry, ignite, and weigh the insoluble silicious
matter. Treat this in the crucible with HF1 and a few drops of
H2SO4, evaporate to dryness, ignite, and weigh. It is evident now
that if the insoluble silicious matter contains calcium, magnesium, Lossbyvoi-
potassium, or sodium, the loss of weight, which in the absence of Wuh HFI
these elements would represent the SiO2 volatilized as fluoride of ^504.
silicon, will be decreased by the amount of sulphuric acid which,
uniting with these elements, remains as a part of the residue in the
crucible. It is a simple operation, however, to fuse this residue

248

ANALYSIS OF IRON ORES.

Si02.

Separation
by citric
acid, am-
monia,
and sul-
phide ot
ammo-
nium.

Danger of
loss by
spirting

with Na2CO3, dissolve in water, acidulate with HC1, heat to boil-
ing, add solution of BaCl2 and filter off, and weigh the precipitated
BaSO4. This being accomplished, calculate the amount of SO3,
and add its weight to the loss by volatilization. The result is the
weight of SiO2. When the ore contains appreciable amounts of
sulphate of barium this method is not admissible.

Separation of Alumina from Ferric Oxide.
Besides the indirect method for determining alumina, it is
sometimes necessary or convenient to make a direct separation.
The method usually taken, the iron and alumina being in solution
in HC1, is as follows : Add to the solution about five times the
weight of the oxides, of citric acid (tartaric acid may be used, but,
as it is liable to contain alumina, citric acid is preferable) and
excess of ammonia. If the solution remains clear, heat to boiling,
and add a fresh solution of sulphide of ammonium until all the
iron is precipitated. If the solution does not remain clear on the
addition of ammonia, acidulate with HC1, add more citric acid, and
then excess of ammonia. Allow the sulphide of iron to settle,
decant the clear liquid through a washed filter, throw the precipi-
tate on the filter, and wash it well with water containing sulphide
of ammonium, changing the beaker into which the washings run
before each addition of wash-water, and keeping the funnel well
covered with a watch-glass. Unite the filtrate and washings, acidu-
late with HC1, boil until the precipitated sulphur agglomerates,
filter into a platinum dish, and evaporate to dryness. Heat care-
fully until the chloride of ammonium is volatilized and there
remains in the dish a mass of carbonaceous matter from the
decomposition of the citric acid. The expulsion of the last traces
of water from the chloride of ammonium nearly always causes loss
by spirting, but the difficulty may be entirely avoided by placing
the dish in one of the holes of the air-bath overnight, after having
lightly coated the upper edge of the dish with paraffine or grease
to prevent the chloride of ammonium from creeping over the top.

SEPARATION OF ALUMINA FROM FERRIC OXIDE. 249

This long heating expels the last traces of water without the least
disturbance, and the dish may be at once placed over a Bunsen
burner, and the mass in it decomposed without fear of loss.
Transfer the carbonaceous matter to a crucible, wiping out the
dish carefully with filter-paper, and placing these in the crucible
also. Burn off the carbon in the crucible, fuse the residue with
Na2CO3 and a little NaNO3, treat with water, transfer to a platinum
dish, dissolve any adhering particles in the crucible in HC1, add
this to the solution in the dish, with enough HC1 to acidulate
it, heat to boiling after diluting, add a slight excess of ammonia,
boil until the solution smells but faintly of NH3, filter, wash
thoroughly, ignite, and weigh as A12O3. This precipitate will AiaO3.
contain any P2O5, Cr2O3, and TiO2 that may have been in the
original solution. They may be separated by the methods given impurities,
on page 189 et seq. It is liable to contain also a little iron,
which is almost invariably held in solution by the sulphide of
ammonium.

Dissolve the precipitate of ferrous sulphide on the filter in
dilute hot HC1, allow the solution and washings to run into the
beaker in which the precipitation was made, add a little HNO3,
evaporate to dry ness, redissolve in as little dilute HC1 as possible,
filter into a platinum dish, dilute, precipitate by ammonia, filter,
wash, dry, ignite, and weigh as Fe2O3. Fe2o3.

Rose * suggested the method based on the solubility of alu- separation
mina in caustic potassa or soda. When the iron and alumina are pou«a <*
in solution, evaporate until syrupy in a platinum dish, add a strong
solution of caustic soda or potassa until the solution is strongly
alkaline, and then add a large excess of the precipitant, and boil
for ten or fifteen minutes ; or, pour the nearly neutral solution of
the chlorides into a boiling solution of caustic soda or potassa in
a platinum or silver dish, in a thin stream, stirring continually.
Filter, wash with hot water, carefully acidulate the filtrate with

* Chimie Anal. Quant. (French ed.), page 148.

250

ANALYSIS OF IRON ORES.

Objection
method.

current of
after ^e-

Rose's mod-

ification.

Separation

by hypo-
sulphite of

HC1, and precipitate the alumina by ammonia, filter, wash, dis-
solve in HC1, evaporate to dryness to get rid of SiO2, redissolve,
filter, and determine as usual. As the Fe2O3 precipitated by caus-
tic soda or potassa always contains alkali, it must be dissolved in
HC1, precipitated by ammonia, filtered, and weighed in the usual
manner.

Rose also suggested fusing the finely-ground ignited oxides
in a silver crucible with potassium or sodium hydrate ; but this
method, as well as the other, is open to the objection that it is
almost impossible to get caustic soda or potassa that does not con-
tain alumina, and generally there would be more in the reagent
than in the ore.

Rivot suggested the following method : After weighing the
ignited oxides of iron and aluminium, grind them very fine, and
weigh them into a porcelain or platinum boat. Place the boat
in a porcelain or platinum tube, and heat to redness in a cur-
rent of hydrogen gas until no more H2O appears to come off.
Replace the hydrogen by a stream of HC1 gas, reheat the tube,
and continue the current as long as ferric chloride is given off.
Remove the boat, and, if the residue is not white, repeat the opera-
tion. Weigh the remaining A12O3, and calculate from the amount
of the oxides used the total amount in the ore.

Rose modified this method by substituting a crucible and tube
for the boat, etc. The apparatus as he used it is the same as
that described for the determination of manganese as sulphide,
page 114.

Wohler suggested the method of separating iron and alumina
by boiling the nearly neutral solution with an excess of hypo-
sulphite of sodium. The following modification of this method*
appears to give excellent results, and has the advantage of doing
away with a subsequent separation of P2O5 in those cases in which
it has not been determined in another portion. The Fe2O3 and

* Communicated to me by Mr. S. Peters in 1879.

DETERMINATION OF NICKEL, COBALT, ETC. 251

A12O3 from I gramme of ore being in solution in HC1, dilute to Peters's
400 or 500 c.c. with cold water, and add ammonia until the solu- tion.
tion becomes dark red in color, but contains no precipitate. Now
add 3.3 c.c. HC1, 1.2 sp. gr., and 2 grammes phosphate of sodium,
dissolved 'in water and filtered; stir until the precipitate formed is
dissolved and the solution becomes perfectly clear again. Add
now 10 grammes of hyposulphite of sodium, dissolved in water
and filtered if necessary, and 15 c.c. of acetic acid, 1.04 sp. gr.,
heat to boiling, boil fifteen minutes, filter as rapidly as possible on
an ashless filter, wash thoroughly with hot water, dry, ignite in a
porcelain crucible, and weigh as A1PO4, which, multiplied by .41847,
gives the weight of A12O3. It is necessary in burning off the pre-
cipitate to raise the heat very carefully until all the carbon has
been burned off, as the A1PO4 may fuse and make it almost
impossible to burn off the carbon.

DETERMINATION OF NICKEL, COBALT, ZINC,
AND MANGANESE.

For the determination of these elements use 3 grammes of Solution of
ore, dissolve in HC1, add a little HNO3 or KC1O3 to oxidize any
FeO in the ore, evaporate to dryness, redissolve in HC1, and evap-
orate a second time if necessary to get rid of all HNO. As noted
on page 235, when the ore contains much organic matter, dissolve
in HC1 (if there is much gelatinous silica, evaporate to dryness or
the filtration will be much retarded), filter, add HNO3 or KC1O3,
evaporate to dryness, redissolve in HC1, and evaporate a second
time if necessary, redissolve in 10 c.c. HC1 and 20 c.c. water, dilute,
filter into a No. 6 beaker, and proceed exactly as directed for the
determination of manganese in iron and steel, page 1 10 et seq.y
until the precipitate by H2S is obtained and filtered off. Deter-

252 ANALYSIS OF IRON ORES.

mine the manganese, if desired, in the filtrate, as directed on page

MnO. 112, and calculate to MnO.

Dry and ignite the precipitated sulphides of nickel, cobalt,
zinc, copper, lead, etc., in a porcelain crucible, transfer to a small
beaker, and dissolve in HC1, with the addition of a drop or two of
HNO3. Evaporate to dryness, redissolve in 10 to 20 drops HC1,
dilute to 50 or 60 c.c., heat to boiling, and pass a current of H2S

Sulphides through the boiling solution. Filter off the precipitated sulphides

of copper,

lead, etc. of copper, lead, etc., and wash with water containing H2S. Evap-
orate to dryness the filtrate, which contains only nickel, cobalt,
and zinc. To the dry salts in the bottom of the beaker add 2
drops of strong HC1, dilute to 150 c.c. with cold water, and pass
H2S through the solution until it is thoroughly saturated with the
gas. If a white precipitate forms, it is sulphide of zinc. Allow
to stand several hours, filter, wash with H2S water (the sulphide
of zinc has a tendency to pass through the filter, and consequently
the beaker into which the filtrate is received must be changed
before the precipitate is poured on the filter), dry, and ignite the
precipitate. Heat it several times with carbonate of ammonium
to drive off any sulphuric acid that may have been formed by the
Zno. ignition, cool, and weigh as ZnO. The precipitate is greenish

white while hot and yellowish white when cold. If it should
carry down a little cobalt from the solution, the ignited precipitate
of ZnO is green when cold. Pass H2S through the filtrate from
the ZnS again, and, if no further precipitate appears, add a few
drops of a solution of .5 gramme of acetate of sodium in 10 c.c.
water. If this occasions a white precipitate, filter it off, after
standing, as in the first instance; but if the precipitate is black
(as it is almost certain to be if the instructions given above are
strictly followed), add the rest of the acetate of sodium solution,
heat the solution to boiling, while the passage of the H2S is con-
tinued, allow the precipitate to settle, filter it off, ignite it, and
treat it as directed for the separation and determination of nickel
and cobalt, page 184 et seq.

DETERMINATION OF COPPER, LEAD, ETC. 253

DETERMINATION OF COPPER, LEAD, ARSENIC,
AND ANTIMONY.

Treat 10 grammes of the very finely ground ore with 50 c.c.
HC1, add a little KC1O3 from time to time, and increase the heat
gradually until the ore is perfectly decomposed. Dilute, filter into
a No. 5 beaker, deoxidize with bisulphite of ammonium, as directed
on page 82, drive off the excess of SO2, and pass H2S through the
solution for fifteen or twenty minutes. Allow the solution to stand
for some hours until the precipitate has settled completely and the
solution smells but faintly of H2S. Filter on a thin felt on the
Gooch crucible or small cone, wash with cold water, and suck dry.
Transfer the felt and precipitate to a small beaker, using a little
asbestos wad in the forceps to wipe off" any adhering precipitate
from the large beaker and the crucible or cone, and digest it with a
few c.c. of a colorless solution of sulphide of potassium. Dilute to Separation
about 100 c.c., filter on another felt, and wash with water contain-
ing a little sulphide of potassium. The solution contains the sul-
phides of arsenic and antimony dissolved in sulphide of potassium,
while the sulphides of copper and lead remain in the felt. Return
the felt with the precipitate to the beaker from which they were
filtered, and digest with HC1, with the addition of HNO3, until all
the black sulphides are dissolved, dilute with a little hot water, and
filter. Evaporate the filtrate, after adding a few drops of H2SO4,
until fumes of SO3 are evolved, allow to cool, dilute with 25 c.c.
cold water, add one-half its bulk of alcohol, allow to settle, filter
the precipitated PbSO4 on the Gooch crucible, wash with alcohol
and water, heat carefully over a low light, and weigh. Treat the
precipitate in the felt under a slight pressure with a strongly am-
moniacal solution of citrate of ammonium, to dissolve the PbSO4,
wash with hot water, and weigh. The difference between the two
weights is PbSO4, which multiplied by .68298 gives the weight
of Pb, or multiplied by 78879 gives the weight of PbS. PbandPbs.

Evaporate the filtrate from the PbSO4 until the alcohol is

254

ANALYSIS OF IRON ORES.

Cu and
Cu2S.

Solution of
sulphides
of arsenic
and anti-
mony by
HC1 and
KC103.

Mg2(NH4)2

As2
Aq.

and
FeAs2.

driven off and the solution reduced to a convenient bulk, transfer
to a platinum crucible, and precipitate the copper on the small
platinum cylinder by the battery, page 182. The weight of Cu
multiplied by 1.25284 gives the weight of Cu2S.

Acidulate the nitrate of sulphide of potassium containing ar-
senic and antimony in solution with HC1, and allow to stand in a
warm place until all the H2S has been driven off and the sulphides
of arsenic and antimony mixed with the excess of sulphur have
settled completely. Filter on a thin felt, wash with warm water,
then with alcohol, and finally with bisulphide of carbon, to dis-
solve the excess of S. Transfer the felt and precipitate to a small
beaker, add 5 c.c. HC1 and a few crystals of KC1O3. Digest at
a low temperature for some time, adding occasionally a small crys-
tal of KC1O3, finally heat a little, but not to a sufficiently high
degree to fuse any little particles of separated sulphur, keeping the
liquid always full of the products of decomposition of the KC1O3.
When all the sulphides of arsenic and antimony are dissolved,
dilute with about 20 c.c. of warm water, and add a few small
crystals of tartaric acid to keep the antimony in solution. Filter
from the asbestos, using as little wash-water as possible in order
to keep down the volume of the solution, add a slight excess of
ammonia to the filtrate, and if it remains clear 5 c.c. of magnesia
mixture and one-third the volume of the solution of NH4HO.
Cool in ice-water, and stir vigorously from time to time to pre-
cipitate the Mg2(NH4)2As2O8-h Aq.

Allow to stand overnight, filter, and determine the arsenic
as directed on page 196. If the acid solution above mentioned
becomes cloudy upon the addition of NH4HO, acidulate care-
fully with HC1, and add a little more tartaric acid. Then proceed
as above directed. The weight of As calculated from the amount
of Mg2As2O7, multiplied by 1.373, gives the weight of FeAs2.

Acidulate the filtrate from the Mg2(NH4)2As2O8 -f Aq, which
contains none of the washings, with HC1 so that the solution is
just acid to test-paper, dilute with hot water to about 250 c.c.,

DETERMINATION OF THE ALKALIES. 2$$

and pass H2S into the solution, heating it gradually to boiling.
Drive off the excess of H2S with a current of CO2, filter on a felt
in the Gooch crucible, wash with water, alcohol, and finally with
bisulphide of carbon to dissolve any free sulphur, dry carefully,
heat to a temperature slightly above 100° C, and weigh as Sb2S3.
For the very small amounts of antimony that are found in iron
ores this method is sufficiently exact. The weight of Sb2S3 mul- sb2s3and
tiplied by .71390 gives the weight of Sb.

DETERMINATION OF THE ALKALIES.

As a rule, the alkalies in iron ores are found exclusively in the
insoluble silicious matter, and when the sum of the weights of the
SiO2, A12O3 etc., CaO, and MgO in the insoluble silicious matter
falls much below the weight of the latter, it is always well to look
for alkalies.

Dissolve 3 grammes of the ore in HC1, evaporate to dryness,
redissolve in 10 c.c. HC1 + 2O c.c. water, dilute, and filter into a
platinum dish. Ignite the insoluble residue, treat it in the crucible Treatment
with HF1 and 10 to 30 drops H2SO4, evaporate down until copious *

fumes of SO3 are given off, dissolve in water with a little HC1 if
necessary, transfer to a small platinum dish, dilute to 100 c.c., heat
to boiling, and add excess of ammonia. Boil for a few minutes,
and filter from the A12OS etc. into another platinum dish. Evapo-
rate the filtrate to dryness, and heat until the chloride and sulphate
of ammonium are volatilized. Treat the residue with a little water,
heat to boiling, and add enough oxalate of ammonium to precipi-
tate all the calcium, filter into another platinum dish, evaporate to
dryness, and heat to dull redness. Treat the residue with a little
water, heat the filtrate to boiling, add enough acetate of barium to
precipitate all the H2SO4, boil, and filter. Evaporate the filtrate to
dryness and heat to redness to decompose the acetates. Treat the

S "

(Tf -NTTVERSIT T

256

ANALYSIS OF IRON ORES.

KC1 +
NaCl.

K2PtCl6.

K20.

KC1.

Nad.

Na2O.

Treatment
of the por-
tion of the
ore soluble
in HC1.

Decompo-
sition of
insoluble
matter by
CaC03
and
HN4C1.

residue with water, filter from the insoluble carbonate of barium,
add a few drops of barium hydrate, and evaporate again to dry-
ness. Dissolve in a few c.c. of water, and filter into a weighed
crucible.

Evaporate very low, and, if nothing separates out, add a few
drops of HC1, evaporate to dryness, heat to very dull redness, cool,
and weigh as KC1 + NaCl. To the residue in the crucible add a
little water, in which the residue should dissolve perfectly, and a
solution of platinic chloride. Evaporate down in the water-bath
until the mass in the crucible solidifies upon cooling, add a little
water to dissolve the excess of platinic chloride, and then an equal
volume of alcohol. Filter on a Gooch crucible, wash with alco-
hol until the filtrate runs through perfectly colorless, dry at 120°
C, and weigh as K2PtCl6. This weight multiplied by .19395 gives
the weight of K2O. Then multiply the weight of K2PtCl6 by
.30696, which gives the weight of KCL Subtract this from the
weight of KC1 -j- NaCl previously obtained, and the difference is
the weight of NaCl, which multiplied by .53077 gives the weight
of Na2O.

To the filtrate from the insoluble silicious matter add an excess
of ammonia, rub a little grease or parafifine on the edge of the
dish, and evaporate the mass to dryness. This will render the
Fe2O3 very compact and granular. Dilute with hot water, add a
few drops of ammonia, filter into another platinum dish, add a
few drops of H2SO4, evaporate to dryness, and ignite to drive off
all the ammonia salts. Then proceed exactly as directed for the
determination of the alkalies in the insoluble silicious matter.
The alkalies in the insoluble silicious matter may also be deter-
mined by J. Lawrence Smith's method of fusion with carbonate of
calcium and chloride of ammonium, as directed farther on.

The chloride of ammonium, which is so troublesome in alkali
determinations, may be decomposed * very easily by evaporating

* J. L. Smith, Am. Jour. Sci. and Art, 1871, $d Ser., vol. i. (whole No. ci.) p. 269.

DETERMINATION OF CARBONIC ACID. 257

the solution down very low, transferring to a tall beaker or flask,
and heating with a large excess of HNO3, — 3 or 4 c.c. HNO3 to NH4ciby
every gramme of NH4C1 supposed to be present. The decom-
position takes place at a temperature below the boiling-point of
water, and when the action seems to be over, transfer to a porce-
lain dish, and evaporate to dryness after adding a few drops of
H2SO4. Dissolve in water, filter into a platinum dish, and pro-
ceed with the analysis in the usual way.

DETERMINATION OF CARBONIC ACID.

Weigh 3 grammes of finely-ground ore into the flask A, Description
- 93 » anc* connect the apparatus in the manner shown in the apparatus,
sketch. L, L are tubulated bottles for forcing a current of air
through the apparatus. The air is deprived of any CO2 which it
may contain by passing through the tube M, which is filled with
lumps of caustic potassa. M is connected with the bulb-tube B by
the tube N, a piece of gum tubing over the slightly tapering end
making an air-tight connection with B. O is a condenser and
serves to condense the steam and acid from the flask A. P
contains anhydrous CuSO4, and Q contains chloride of calcium.
The potash-bulb and the drying-tube R form the absorption
apparatus, and S is a safety-tube filled with CaCl2 to prevent R
from absorbing moisture from the atmosphere. Weigh the ab-
sorption apparatus with the precautions mentioned on page 146,
and connect the apparatus. Close the stopcock C, and draw a Details
little air through the apparatus by means of a piece of gum ofthe
tubing attached to the end of S. Allow the tension of the air
to draw the solution up into the rear limb of the potash-bulb,
and if it remains there for a reasonable length of time the con-
nections may be considered tight. Pour into the bulb B 10
c.c. HC1 diluted with about 65 c.c. water, connect the tube

258

ANAL YSIS OF IRON ORES.

DETERMINATION OF COMBINED WATER. 2-g

N, and by means of the stopcock C allow the acid to flow slowly
into the flask A. When the acid has all run in, by opening
slightly the stopcock in L, start a slow current of air through the
apparatus. Warm the flask A, gradually increasing the heat until
the solution boils, and continue the application of heat until a
considerable amount of water has condensed in O. Allow it to
cool while the current of air is continued, detach, and weigh the
absorption apparatus. The increase of weight is the weight of
CO,. co2.

DETERMINATION OF COMBINED WATER AND
CARBON IN CARBONACEOUS MATTER.

The ores are very rare indeed in which the combined water
can be accurately determined by simply heating them in a cruci-
ble and calling the loss by ignition "Water of Composition." LOSS by

ignition,

Nor is the method of absorbing the moisture, driven off by heat,
in a drying-tube much more reliable. The presence of pyrites, of
organic matter, of graphite, and of binoxide of manganese serves to
complicate the problem. The water of composition may indeed Combustion

with chro-

be determined with great accuracy by heating the ore in a tube mate of

with chromate of lead and bichromate of potassium, exactly as de-
scribed for the determination of carbon in iron and steel by direct
combustion, page 132^ seq. The increase of weight of the U tube
which is attached to the end of the combustion-tube (and which
should be filled in this case with granulated dried CaCl2) is the
weight of "Combined Water" in the amount of ore used. By Combined
attaching the absorption apparatus we likewise obtain the total
CO2 in the ore, or that existing as CO2 in the carbonates, and
that due to the oxidation of any carbon existing as carbonaceous
or organic matter or as graphite. By subtracting from the weight
of CO2 thus obtained the amount of CO2 existing as carbonate
and determined by the method last given, and multiplying the

26O

ANALYSIS OF IRON ORES.

Details
of the
method.

difference by .27273, we get the weight of " Carbon in carbona-
When it is necessary to make a large number of
these determinations, the matter is very much simplified by using
the apparatus shown in Figs. 95 and 96.* Fig. 95 shows the
details of a form of tubulated platinum crucible suggested by Dr.
Gooch, which consists of the crucible with a flange at d into which
fits the cap. This cap consists of a conical cover, H, drawn up

FIG. 95.

Carbon in
carbona-
ceous mat- ceous matter."

Tubulated
crucible.

-1 INCHES

vertically into the tube I. The horizontal tube J is burned into I,
and through the centre of I passes the small tube K, which,
expanding at a, is burned into I at this point, sealing it securely.
The tubes N and M of glass are fused to K and J at C and b
respectively. In analyzing ores containing much water or car-
bonic acid, use I gramme ; for others, use 3 grammes. Weigh the
finely-ground ore into a small agate mortar, and mix it thoroughly
with 7 to 10 grammes of previously fused bichromate of potas-
sium, transfer it to the crucible A, Fig. 96, and place it in an air-bath

* Tenth Census of the U. S., Mining Industries, vol. xv. p. 519.

DETERMINATION OF COMBINED WATER.

heated to 100° C. to drive off any hygroscopic moisture. When
perfectly dry, attach the cap B to the crucible, and stand the latter
in the triangle C. Close the end N .with a piece of rubber tubing
in the other end of which is fitted a piece of glass rod. Attach
the weighed drying-tube D, filled with CaCl2, to the horizontal
tube from B, by means of a thoroughly dried velvet cork. Attach
the absorption apparatus E and F and the safety-tube G. Fill the
outside of the flange d with small pieces of fused tungstate of

FIG 96.

26l

sodium, and, with a blow-pipe flame, melt them, having previously
immersed the lower end of A in a small beaker of ice-water. The
expansion of the air in the crucible by the heat applied to melt the
tungstate of sodium will force some bubbles through the potash-
bulb E, and the subsequent cooling of the air in A will cause the
liquid in E to flow back into the rear bulb. If the difference of
level thus produced be maintained for some minutes, the connec-
tions may be considered tight. Connect N with the bottles L, as
shown in the sketch, and start a current of air through the appara-
tus. The air is purified from CO2 and moisture by passing through
Q, which is filled with fused caustic potassa. Now, by means of the

262 ANALYSIS OF IRON ORES.

blast-lamp P, heat the crucible just above the top of the mixture,
and gradually carry the heat downward, increasing it at the same
time. This will keep the mixture from frothing and choking the
tube. Finally, heat the bottom of the crucible by the burner O,
and continue the application of the heat for ten minutes. During
the whole of the operation the air passes through N and K into
the crucible and out through J and M (Fig. 95) into D (Fig. 96),
and so through the apparatus. The moisture from the ore should
not be allowed to condense in the wide part of D at ft but should
be driven forward into the CaCl2 by warming the tube at f with
the flame from an alcohol lamp. Allow the apparatus to cool
while the current of air is continued, then detach, and weigh the
tube D and the absorption apparatus, and calculate the results, as
directed on page 259. When detached from the apparatus, the
wide end of the tube D may be closed by a short cork, covered
with tin-foil to prevent the absorption of moisture from the atmos-
cieaningthe phere. To clean the crucible, remove it from the stand, and, hold-

crucible. ... . r i • •

ing it in a piece ot asbestos board in an inclined position, melt the
tungstate of sodium in the flange d with a blow-pipe flame and
detach the cap. Dissolve out the bichromate by placing the cruci-
ble in a dish of hot water, clean out the ore, dissolve any adhering
oxide in HC1, wash the crucible and cap with hot water, dry them,
and they will be ready for another determination.

DETERMINATION OF CHROMIUM.

The small amount of chromium which is found in some iron
ores is generally converted into chromate of sodium very readily
by fusion with Na2CO3 and KNO3. Fuse I or 2 grammes of the
finely-ground ore with 10 times its weight of Na2CO3 and a little
KNO3. Treat the fused mass with water and wash it out into
a small beaker. If the solution is colored by manganese, add a

DETERMINATION OF CHROMIUM. 263

little alcohol, which will precipitate the manganese, leaving the indication

solution, if chromium is present, slightly yellow. If the solution presence
is colorless it may be considered proof of the absence of chro-

mium. Otherwise filter, wash the insoluble matter on the filter,
dry it, grind it with ten times its weight of Na2CO3 and a little
KNO3, fuse it, treat with water as before, filter, and add this filtrate
to the other. Acidulate the combined filtrates with HC1, evaporate
to dryness to render the silica insoluble, and reduce the chromic
acid to Cr2O3. Treat the mass with HC1, dilute, filter, and precipi-
tate the Cr2O3 -+- A12O3 by ammonia. Boil for some minutes, filter,
wash well with hot water, dry, and ignite the precipitate. Fuse
with as little Na2CO3 and KNO3 as possible, treat with water, and
wash the solution into a platinum dish. Evaporate the solution separation
until it is very concentrated, adding from time to time crystals of Ai2o8.
nitrate of ammonium to change all the carbonated and caustic
alkali to nitrate. At each addition of the nitrate of ammonium
the solution effervesces, and carbonate of ammonium is given off.
When the solution is nearly syrupy, the addition of nitrate of am-
monium no longer causes an effervescence, and the solution smells
faintly of ammonia, add a few drops of NH4HO, and filter. By
this operation all the alumina, phosphate of aluminium, oxide of
manganese, etc., are precipitated, and there remain in solution
only the alkalies and the chromate of the alkalies. To the fil-
trate add an excess of sulphurous acid in water, which instantly
changes the color of the solution from yellow to green. Boil well,
add an excess of ammonia, boil for a few minutes, filter on an
ashless filter, wash well with hot water, dry, ignite, and weigh
as Cr2O3. Crso8.

Chrome iron ore is best decomposed by Genth's * method of chrome
fusing .5 gramme of very finely ground ore with bisulphate of
potassium, raising the heat very gradually until finally the highest
temperature of the lamp is attained, allowing it to cool, adding

* Chem. News, vol. vi. p. 31.

264 ANALYSIS OF IRON ORES.

5 grammes Na2CO3 and I gramme KNO3, and heating gradually
to complete fusion, allowing it to remain so for fifteen or twenty
minutes, treating with water, and proceeding as directed above.

DETERMINATION OF TUNGSTEN.

Digest from i to 10 grammes of the ore in HC1, adding HNO3
from time to time. When the ore appears to be perfectly decom-
posed, evaporate to dryness on the water-bath (a higher tem-
perature is not admissible, as it may render the WO3 insoluble
in NH4HO), redissolve in HC1, and evaporate down again. Re-
dissolve in HC1, dilute, filter, wash with acidulated water, and
finally with alcohol. Treat on the filter with ammonia, allowing
the filtrate to run into a platinum dish, evaporate to small bulk,
add excess of ammonia, filter, if necessary, into a platinum cru-
cible, evaporate carefully to dryness, heat gently to drive ofT the
ammonia, and ignite. Weigh as WO3.

DETERMINATION OF VANADIUM.

Fuse 5 grammes of the very finely ground ore with 30
grammes of Na2CO3 and from I to 5 grammes of NaNO3, and
proceed exactly as in the determination of vanadium in pig-iron,
page 199. A second fusion of the residue from the aqueous
solution of the first fusion is hardly ever necessary.

DETERMINATION OF SPECIFIC GRAVITY.

265

FIG. 97.

DETERMINATION OF SPECIFIC GRAVITY.

The specific gravity of iron ores is determined with much
greater accuracy by using the powdered material than by using
lumps of the ore. The little flask
shown in Fig. 97 was designed for this
purpose by the late Mr. James Ho-
garth,* and its use avoids two diffi-
culties experienced in the use of the
ordinary specific gravity bottle, — the
expansion and overflow consequent
upon transferring the flask at 60° F.
to the higher temperature of the bal-
ance-case, and the necessity for wait-
ing until the finely-divided particles
of the ore shall have settled before
inserting the stopper. These difficul-
ties were overcome by melting a capil-
lary tubulus to the lower part of the
neck of the flask, and by grinding in

a stopper having a small bulb above the capillary, to allow for
expansion. The operation is conducted as follows : Transfer a
weighed amount of the ore to the flask, add enough water to
cover it, and heat it almost to the boiling-point by placing it in
the water-bath. Place the flask under a bell-jar connected with
an aspirator or air-pump, and expel all the air by allowing it to
boil for some time at a reduced pressure. Remove it from the
bell-jar, fill it up to the tubulus with cold water, insert the stopper,
and cool the flask and its contents to about 60° F. By suction
on the stopper draw water through the tubulus until it is slightly
above the capillary of the stopper, at which point a mark is
scratched. When the flask and its contents are exactly at 60° F.,

Hogarth's
flask.

Its advan-
tages.

* Tenth Census of the U. S., vol. xv. p. 522.

ANALYSIS OF IRON ORES.

adjust the volume exactly to the mark on the capillary by touch-
ing a piece of blotting-paper to the end of the tubulus or by draw-
ing a little water in through it. Dry the flask, allow it to acquire
the temperature of the balance-case, and weigh it. Now, if W is
the weight of ore taken, W the weight of the ore and water at
60° F., and K the weight of the flask and its contents to the
mark of water at 60° F., then

W
Sp-gr' = W+K-W

To obtain I£, fill the flask with boiled water, and treat it exactly
as described above.

METHODS FOR THE ANALYSIS

LIMESTONE.

DETERMINATION OF INSOLUBLE SILICIOUS
MATTER, ALUMINA AND OXIDE OF IRON,
CARBONATE OF CALCIUM, AND CARBONATE
OF MAGNESIUM.

WEIGH I gramme of the powdered limestone, previously dried
at 1 00° C., into a No. I beaker, cover with a watch-glass, and
pour in 5 c.c. of HC1 diluted with 25 c.c. of water and a little
bromine-water. Digest on the sand-bath until all the action
ceases, wash the watch-glass with a fine jet of water, and evap-
orate to dryness. Redissolve in 10 c.c. HC1 diluted with 50 c.c.
water, filter on a small ashless filter, wash well with hot water,
dry, ignite, and weigh as Insoluble Silicious Matter. Heat the fil- insoluble
trate to boiling, add a slight excess of ammonia, boii for a few Matter.8
minutes, filter, wash once or twice. Dissolve the precipitate on Resolution
the filter in a little dilute HC1, allowing the solution to run into ^^
the beaker in which the precipitation was made, wash well with a'piAtft"

Of AloOs

water, dilute, boil, and reprecipitate by ammonia. Filter on a andFe2o3.
small ashless filter, allow this filtrate to run into the beaker con-
taining the first one, wash well with hot water, dry, ignite, and Ai2o3and
weigh as A12O3 and Fe2O3. Heat the united filtrates to boiling, Quantity of
add enough oxalate of ammonium to convert all the calcium and ammo.
magnesium into oxalates.* Allow the precipitate of oxalate of

cessary.

25 c.c. of the saturated solution is about the proper quantity.

267

268

ANAL YSIS OF LIMESTONE.

CaO.

CaC03

Quantity of
microcos-
mic salt
required.

MgO and
MgC03.

Other sub-
stances
found in
lime-
stones.

calcium to settle for fifteen or twenty minutes, filter on an ash-
less filter, wash with hot water, dry, ignite for some time over a
Bunsen burner, and finally for fifteen minutes at the highest tem-
perature of a blast-lamp. Cool in a desiccator, weigh quickly,
ignite again over the blast-lamp for five minutes, cool, and weigh
again. If this weight is the same, or nearly the same, as the
previous one, call the amount CaO. If the second weight is
much less than the first, ignite, and weigh again until the weight
is constant. The weight of CaO multiplied by 1.78459 gives the
weight of CaCO3. Add to the filtrate from the oxalate of cal-
cium 30 c.c. of a saturated solution of microcosmic salt (phos-
phate of sodium and ammonium), acidulate with HC1, and evap-
orate the solution to about 300 c.c. If during the evaporation
any precipitate should separate out, redissolve it in HC1. Cool
the evaporated solution in ice-water, and add ammonia drop by
drop, stirring the solution, but being careful to avoid rubbing
the sides of the beaker with the rod, as the precipitate of
Mg2(NH4)2P2O8 -J- I2H2O is liable to adhere with great tenacity
to those points or lines where the rod has touched the sides or
bottom of the beaker. Continue the addition of ammonia until
the solution is decidedly alkaline, and then add an amount equal to
one-fourth of the neutralized solution. After the precipitate has
begun to form, stir vigorously several times, allow to stand over-
night, filter on an ashless filter, rub off with a " policeman" any
of the precipitate that may adhere to the beaker, wash with a
mixture of I part ammonia and 2 parts water, containing 100
grammes of nitrate of ammonium to the litre, dry, ignite with
great care, as directed on page 85, cool, and weigh as Mg2P2O7,
which multiplied by .36212 gives the weight of MgO, and multi-
plied by .75760 gives the weight of MgCO3.

Limestones, besides the ordinary constituents mentioned
above, may contain small amounts of phosphoric acid, sulphur
as sulphate or as pyrites, titanic acid, organic matter, combined
water, alkalies, manganese, fluorine, and in rare instances nearly

DETERMINATION OF PHOSPHORIC ACID. 269

all the metals found in iron ores. For most of these the methods
described in the analysis of iron ores may be employed. Very
often the amounts of silica and alumina are required in calculating
mixtures for the blast-furnace, and, as the matter insoluble in HC1
consists usually of silicates of alumina, lime, and magnesia, it Determina-
would be necessary in accurate work to decompose the Insoluble Sio2.
Silicious Matter by fusion with carbonate of sodium and to make
a separate analysis of it, as described on page 239. It is, indeed,
much better to make the analysis in this way than to add the
filtrate from the silica to the main solution, for the oxalate of
calcium is sure to carry down some of the sodium salts with it
and thus very materially complicate the analysis.

After weighing the A12O3 and Fe2O3 from the Insoluble Silicious
Matter and that from the portion soluble in dilute HC1 to deter-
mine the Fe2O3, fuse the two precipitates with a little carbonate
of sodium, dissolve in water, acidulate with HC1 in a beaker, add
a few small crystals of citric acid to the clear solution, then excess
of ammonia and sulphide of ammonium. Allow the precipitate of
sulphide of iron to settle, filter, wash slightly, dissolve in HC1, add
a little bromine-water, boil the solution, precipitate by ammonia,
filter, wash, ignite, and weight as Fe2O3. The weight of Fe2O3 Fe2o3.
subtracted from the weight of the total A12O3 -f Fe2O3 gives, of Ai2o3.
course, the weight of A12O3.

The CaO and MgO in the Insoluble Silicious Matter should not Cao and

MgOin

be calculated as carbonates, but should be considered as existing insoluble

r+ r\ i T\T r\ Silicious

as CaO and MgO. Matter.

To determine phosphoric acid in limestones, treat 20 grammes Determina-
with dilute HC1, filter from the Insoluble Silicious Matter, to the p°o6°
filtrate add a few drops of ferric chloride solution, then ammonia
until the solution is alkaline to litmus-paper,* and acetic acid to
decided acid reaction. Boil for a few minutes, filter, wash once

* If the precipitate is not decidedly red in color, acidulate with HC1 and add
more ferric chloride solution.

2/0

ANALYSIS OF LIMESTONE.

Treatment
of In-
soluble
Silicious
Matter.

Treatment
of In-
soluble
Silicious
Matter
by direct
fusion.

Sulphur in
limestone.

with hot water, dissolve in HC1 on the filter, allowing the solution
to run into the beaker in which the precipitation was made, add
the solution from the treatment of the Insoluble Silicious Matter
mentioned below, dilute, and reprecipitate exactly as before with
ammonia and acetic acid. Dissolve this precipitate on the filter
in dilute HC1, allowing the solution to run into a No. I beaker,
wash the filter with hot water, evaporate the solution down almost
to dryness, and precipitate the P2O5 as directed on page 85.

Ignite the Insoluble Silicious Matter, treat it with HF1 and a
few drops of H2SO4, evaporate until fumes of SO3 are given off,
fuse with Na2CO3, digest in water, filter, acidulate the solution
with HC1, and add it to the solution of the first precipitate in the
soluble portion as mentioned above.

Instead of treating the Insoluble Silicious Matter with HF1 and
H2SO4, it may be fused at once with Na2CO3, the fused mass
treated with water, filtered, the filtrate acidulated, evaporated to
dryness, redissolved in water slightly acidulated with HC1, filtered,
and the filtrate added to the solution of the first precipitate by
ammonia and acetic acid as above.

To determine sulphur in limestone, fuse I gramme with
Na2CO3 and KNO3 exactly as in the determination of sulphur in
iron ores, page 226 et seq.

To determine sulphates, proceed as in the analysis of iron ores
for these substances, page 228 et seq.

METHODS FOR THE ANALYSIS

CLAY.

CLAY is essentially silica, mixed with silicates of aluminium,

. . tion of

calcium, magnesium, potassium, and sodium. These silicates are ciay.
hydrated, so that clay usually contains from 6 to 12 per cent, of
water of composition. Besides these usual constituents, clay may
contain oxide of iron, titanic acid, pyrites, organic matter, phos-
phoric acid, and occasionally some of the rarer elements, such
as vanadium.

Clay being practically unacted on by HC1, it is necessary to Method of
proceed as follows : Fuse I gramme of the finely-ground clay
dried at 100° C. with 10 grammes of Na2CO3 and a very little
NaNO3. Run the fused mass well up on the sides of the crucible,
allow it to cool, and treat it with hot water until thoroughly disin-
tegrated, transferring the liquid from time to time to a platinum
dish. Treat the crucible with HC1, add this to the liquid in the
dish, acidulate with HC1, and evaporate to dryness in the air-bath.
Treat the mass with water and a little HC1, evaporate again to
dryness, and treat with 15 c.c. HC1 and 45 c.c. water. Allow it
to stand in a warm place for fifteen or twenty minutes, add 50
c.c. water, and filter on an ashless filter. Wash thoroughly with
hot water acidulated with a few drops of HC1, dry, ignite, heat for
three or four minutes over the blast-lamp, and weigh. Treat the
precipitate with HF1 and a few drops of H2SO4, evaporate to dry-
ness, ignite, and weigh. The difference between the two weights is

271

2/2
SiO2.

A1203 +
Fe203.

A1203.

CaO and
MgO.

Determina-
tion of
alkalies.

ANALYSIS OF CLAY.

SiO2. If any appreciable residue remains in the crucible, treat it
with a little HC1, and wash it out into the filtrate from the silica.
Transfer the filtrate from the silica to a large platinum dish, heat
it to boiling, add an excess of ammonia, boil until the smell of
NH3 is quite faint, filter on an ashless filter, and wash several
times with hot water. Stand the filtrate and washings aside, and
treat the precipitate on the filter with a mixture of 15 c.c. HC1
and 15 c.c. water, cold. Allow the solution to run into a small
clean beaker, replace this by the platinum dish in which the pre-
cipitation was made, pour the solution on the filter again, and
repeat this operation until the precipitate has completely dissolved.
Wash, out the beaker into the filter, wash the latter thoroughly
with cold water, dry, and preserve it. Reprecipitate by ammonia,
as above directed, filter on an ashless filter, wipe out the dish with
small pieces of filter-paper, add these to the precipitate, and wash
thoroughly with hot water. Dry, ignite the precipitate and filter,
and the filter from the first precipitation, heat for a few minutes
over the blast-lamp, cool, and weigh as A12O3 and Fe2O3. Fuse
the ignited precipitate with Na2CO3, treat the fused mass with
water, wash it out into a small beaker, allow the residue to
settle, decant off the clear, supernatant fluid, treat the residue with
HC1, and determine the iron volumetrically, or add citric acid and
ammonia, and precipitate the iron as sulphide. Filter, wash, dis-
solve in HC1, oxidize with bromine-water, and precipitate the
Fe2O3 by ammonia. Filter, wash, dry, ignite, and weigh as Fe2O3.
Subtract the weight of Fe2O3 from the A12O3 -f Fe2O3 found above,
and the difference is A12O3.

As the amounts of calcium and magnesium in clay are very
small, the filtrate and washings from the second precipitation of
A12O3 + Fe2O3 may be rejected and the CaO and MgO deter-
mined in the first filtrate as directed on page 240.

To determine the alkalies in clay, treat 2 grammes of the finely-
ground material in a platinum dish with 4 c.c. of strong H2SO4
and 40 or 50 c.c. of redistilled HF1. Stir it from time to time

DETERMINATION OF THE ALKALIES. 273

with a platinum wire or rod, heating carefully, until the clay is
entirely decomposed and no more gritty substance can be felt HFiand

TT C(")

under the rod. Evaporate to dryness, and heat until fumes of
SO3 are given off. The entire operation should be carried on
under a hood with a good draft, as HF1 is very poisonous, and the
evaporation may be safely conducted on the little arrangement
shown in Fig. 10, page 20. Allow the dish to cool, add about
50 c.c. water and a little HC1, and heat until the mass is all dis-
solved. If any of the clay has escaped decomposition, filter into
another platinum dish, wash the insoluble matter on the filter,
dry, ignite, and decompose it in the crucible with HF1 and H2SO4.
Dissolve the mass in the crucible after evaporating off the HF1,
and add the solution to the main solution in the dish. Dilute
this solution to 300 or 400 c.c. with hot water, heat to boiling, add
an excess of ammonia, boil for a few minutes, and filter. Allow washing
the precipitate to drain well on the filter, remove the filtrate, which delated
should be in a platinum dish, to a light, and evaporate it down.
Pierce the filter with a wire or rod, and wash the precipitate into
the dish in which the precipitation was made with a jet of hot
water. Dilute to 300 or 400 c.c., add a little ammonia, heat to
boiling, filter, and wash several times with hot water. Add this
filtrate to the first one, and evaporate to dryness. Heat until
all the ammonium salts are volatilized, and proceed exactly as
directed for the determination of alkalies in the Insoluble Silicious
Matter from iron ores, page 255.

Instead of decomposing the clay by HF1 and H2SO4, the J. Lawrence
method given by J. Lawrence Smith may be used for determining method for
alkalies. Weigh I gramme of the finely-ground clay into a por-
celain or agate mortar, add an equal weight of granular chloride
of ammonium,* and grind the two together to mix them. Add
8 grammes of carbonate of calcium,f and grind the entire mass
so as to obtain an intimate mixture of the whole. Transfer to a

See page 45. f See page 52.

274

ANALYSIS OF CLAY.

capacious platinum crucible, cover with a close-fitting lid, and
heat carefully to decompose the chloride of ammonium, which is
accomplished in a few minutes. Heat gradually to redness, and
keep the bottom of the crucible at a bright red for about an hour.
Allow the crucible to cool, and if the mass is easily detached from
the crucible, transfer it to a platinum dish and add about 80 c.c.
of water. Wash off the lid into the crucible with water, heat this
to boiling, and wash the crucible out into the dish. Heat the
water in the dish to boiling, and, when the mass has completely
slaked, filter into another platinum dish and wash the mass on the
filter with hot water. If the semi-fused mass in the crucible is not
easily detached, place the crucible on its side in the dish, wash off
the lid into the dish, add about 100 c.c. water, and heat until the
mass disintegrates. Remove the crucible, wash it off into the
dish, and filter as above directed. To the filtrate add about i y2
grammes of pure carbonate of ammonium, evaporate on the
water-bath, or very carefully over a light, until the volume of the
solution is reduced to about 40 c.c., add a little more carbonate
of ammonium and a few drops of ammonia, and filter on a small
filter. Evaporate the filtrate carefully after adding a few drops
more of carbonate of ammonium to make certain that all the cal-
cium has been precipitated. If any further precipitate appears,
filter into a platinum crucible and evaporate to dryness. Heat
carefully to dull redness to drive off any ammonium salts, and
weigh the residue as KC1 + NaCl. Separate the potassium and
sodium as directed on page 256.

Water of Determine the water of composition by igniting I gramme of

rt°nlp° the clay for twenty minutes at a bright red heat, when the loss

of weight will represent the water. In the presence of much

organic matter or pyrites the method given for the determination

of water of composition in iron ores, page 259, may be used.

Determina- To determine titanic acid, treat 2 grammes of the finely-

Tio2. ground clay in a large platinum crucible with HF1 and 5 c.c.

H2SO4. Evaporate off the HF1, and heat carefully until the

DETERMINATION OF TITANIC ACID.

275

greater part of the H2SO4 is volatilized. Allow the crucible to
cool, add 10 grammes of Na2CO3, and fuse for thirty minutes at
the highest temperature obtainable by a Bunsen burner. Run the
fused mass well up on the sides of the crucible, and allow it to
cool. Treat the fused mass with water, transfer it to a beaker, and
filter. Wash the insoluble matter slightly on the filter, dry, ignite,
and fuse it again with Na2CO3. Dissolve in water as before, and
filter. By this method of treatment nearly all the alumina will be
dissolved and separated from the titanic acid. Fuse the insoluble
matter left on the filter with Na2CO3, and determine the TiO2 as
directed on page 179.

When alkalies are determined, the precipitated alumina may Determina-

tion of
be used for the determination of TiO2. In this case dry the pre- Tio2m

cipitate of A12O3, etc., separate it from the filter, ignite the two tion taken

filters, add the ash to the dried, not ignited, precipitate of A12O3,

alkalies.

etc., and fuse with Na2CO3 as above. n°nof

1 •

METHODS FOR THE ANALYSIS

SLAGS.

Composition BLAST-FURNACE slags contain silica, alumina, lime, magnesia,

of blast-
furnace and alkalies always, generally also ferrous oxide, manganous

oxide, and sulphur, and occasionally titanic acid, small amounts
of phosphoric acid, and such metallic oxides as may exist in the
ores, fluxes, or fuel used in the furnace. Sulphur, which is occa-
sionally present in considerable amounts, is considered to exist in
the slag as sulphide of calcium.

The method used for the determination of the principal in-
gredients depends upon whether the slag is capable of being
entirely or but partially decomposed by HC1.

In the first case weigh I gramme of the finely-ground slag
into a platinum or porcelain dish, add 20 c.c. of water, and shake
the dish until the material is thoroughly disseminated through the
siags de- water. Add gradually 30 c.c. HC1, with constant stirring, and
by HCI. finally heat the dish carefully. The slag will dissolve completely
to a clear liquid, but, after heating for a short time, will suddenly
form a solid jelly. Evaporate carefully to dryness, treat with a
few c.c. of dilute HCI and a little bromine- water, evaporate again
to dryness, and add 15 c.c. HCI and 45 c.c. water. Allow to
stand fifteen or twenty minutes in a warm place, add 50 c.c. water,
filter on an ashless filter, wash thoroughly with hot water, dry,
ignite, and weigh. Treat the material in the crucible with a little

water, add 2 or 3 drops H2SO4 and enough HF1 to dissolve it.
276

DETERMINATION OF SILICA, ALUMINA, ETC. 277

Evaporate to dryness, ignite, and weigh. The loss of weight

is SiO2. Sio2.

Any residue in the crucible after the volatilization of the SiO2 Non-voiatiie
is to be added to the A12O3 -f- Fe2O3. Heat the filtrate obtained
above, diluted to 500 c.c., to boiling, add a slight excess of ammo-
nia, boil for a few minutes, filter on an ashless filter, and wash two
or three times with boiling water. Stand the filtrate aside, and
pour on the precipitate in the filter a mixture of 15 c.c. HC1 and
30 c.c. cold H2O, allowing the solution to run into the dish in
which the precipitation was made. Alumina precipitated in this
way seems generally to dissolve more readily in cold than in hot Resolution
dilute HC1, but it is often necessary to break up the precipitate on dpitated
the filter with a rod, to pour the acid solution back on the filter
several times after it has run through, and sometimes to pierce
the filter with a rod or wire and wash the precipitate still undis-
solved into the dish. Wash the filter well with water, dry it, and Preservation

of the

keep it to ignite with the A12O3, etc. Heat the filtrate and wash- filter.

ings to boiling, reprecipitate by ammonia, filter on an ashless filter,

clean off any adhering precipitate from the dish with filter-paper,

add it to the precipitate on the filter, wash well with hot water,

dry, ignite, after adding the filter on which the first precipitation

was filtered, and weigh as A12O3, etc. Add to this the weight of

the residue from the treatment of the SiO2 by H2SO4 and HF1,*

and the sum is the total A12O3 + Fe2O3 + P2O5 + TiO2. Ai2o3,etc.

Evaporate down to about 300 c.c. the two filtrates obtained above,
transfer to a No. 3 beaker, add a few drops of ammonia and enough
sulphide of ammonium to precipitate the manganese. Filter off, and
determine the manganese as directed on page 234, in the " Analysis Mno.
of Iron Ores." To the filtrate from the sulphide of manganese add
a slight excess of HC1, boil until all the H2S is driven off, filter
from any precipitated sulphur, and determine the CaO and MgO CaOand
as directed on page 259 et seq., in the " Analysis of Limestone."

* This residue should be examined for CaO.

ANALYSIS OF SLAGS.

Determi-
nation of
FeO.

Slags con-
taining no
manga-
nese.

Slags that
are not
entirely
decom-
posed
by HC1.

Reprecipi-
tation of
the CaO.

Determi-
nation of
sulphur
in slags.

Alkalies,
TiO2, etc.

Converter
slags, etc.

To determine the FeO, fuse the ignited precipitate of A12O3,
etc., obtained above, with 5 grammes of carbonate of sodium, at
a very high temperature, for at least thirty minutes. Allow the
crucible to cool, treat the fused mass with water, transfer to a
beaker, allow the insoluble matter to settle, decant the clear,
supernatant liquid through a filter, and treat the residue with HC1.
Pour the solution through the filter to take up any iron that may
have been suspended in the liquid decanted through it, and deter-
mine the iron volumetrically or by precipitation as sulphide in the
solution to which citric acid and an excess of ammonia have been
added, as on page 248.' When the slag contains no appreciable
amount of manganese, the precipitation by sulphide of ammonium,
page 277, may be omitted and the CaO precipitated at once from
the concentrated solution.

For the analysis of slags that are not entirely decomposed by
HC1, recourse must be had to fusion with Na2CO3 and a little
NaNO3, exactly as described for the analysis of clay, page 271
et seq. After filtering off the SiO2 as directed, page 271, proceed
with the analysis as described for slags decomposed by HC1, page
277 et seq. As, however, the oxalate of calcium is very liable to
carry down sodium salts with it, it is always well, after igniting
the oxalate of calcium, to dissolve it in dilute HC1, transfer the
solution to a platinum dish, dilute to 300 c.c. with hot water,
add an excess of ammonia, and precipitate boiling by 30 c.c. of a
saturated solution of oxalate of ammonium. Filter, wash, ignite,
and weigh in the usual manner.

For the determination of sulphur in slags, fuse I gramme with
Na2CO3 and a little KNO3, and proceed exactly as directed for the
determination of sulphur in iron ores, page 226 et seq. Calculate
the total sulphur as CaS and the remainder of the calcium as CaO.

For the determination of alkalies, titanic acid, etc., proceed as
directed for the determination of these substances in clay.

Converter slags, open-hearth slags, refinery slag, tap cinder,
mill cinder, etc., are analyzed by the methods described for the

DETERMINATION OF PHOSPHORIC ACID.

analysis of iron ores. In the case of slags obtained from the Analysis of
manufacture of steel by the basic process, which usually contain
very large amounts of phosphoric acid, proceed as follows : Treat
I gramme of the finely-ground slag in a small beaker with 1 5 c.c.
HC1 and a little HNO3 until it is decomposed. Evaporate to dry-
ness, redissolve in 10 c.c. HC1 and 20 c.c. H2O, dilute, filter off,
and weigh the SiO2. To the filtrate diluted to 500 c.c. add a solu- siO2.
tion of ferric chloride and a slight excess of ammonia, if the pre-
cipitate is not decidedly red in color, acidulate carefully with HC1,
add more ferric chloride solution, and then a slight excess of
ammonia. Add acetic acid to slight acid reaction, heat to boiling,
filter and wash slightly with boiling water, stand the filtrate aside,
and dissolve the precipitate on the filter in HC1, allow the solution
to run into the beaker in which the precipitation was made, wash
the filter thoroughly with cold water, dilute the filtrate to about
400 c.c., add a slight excess of ammonia, and then acetic acid,
boil, and filter as before. Add this filtrate to the first, evaporate
down, and determine the manganese, calcium, and magnesium, as
directed in the case of blast-furnace slags, page 277. Dissolve the Mno, Cao,
precipitate on the filter in HC1, dissolving any iron that may
adhere to the beaker in a few drops of the same acid, pour it on
the filter, and wash the beaker and filter well with water. Allow
the solution and washings to run into a No. 3 beaker, add about
10 grammes of citric acid and an excess of ammonia. To this
solution, which should be cold, and should measure about 300 c.c.
add, drop by drop, 50 c.c. of magnesia mixture, stirring carefully,
without touching the sides of the beaker with the rod. Add about
one-third the volume of the solution of ammonia, allow the beaker
to stand in ice-water for some time, stir vigorously several times,
and after a few hours filter (preferably on a Gooch crucible), wash
with ammonia-water of the usual strength, ignite carefully, and p^
weigh as Mg2P2O7. Any alumina in the slag will be in the fil-
trate from the phosphate of ammonium and magnesium, and may
be determined by the method on page 248. Determine the iron

280 ANALYSIS OF SLAGS.

Feo. volumetrically in a separate portion, and calculate to FeO. Deter-

mine any other elements present by the methods under " Analysis
of Iron Ores."

Phosphoric acid cannot well be determined in basic slags by
fusion with Na2CO3, as phosphate of calcium is not readily decom-
posed by this method, and its employment may lead to error.

METHOD FOR THE ANALYSIS

FIRE-SANDS.

As sand contains comparatively very small amounts of alumina,
lime, and magnesia, and a very large amount of silica, it is best
to proceed as follows in the analysis : Weigh 2 grammes of the Treatment
finely-ground sand into a large platinum crucible, moisten it Tnd
with cold water, add 6 or 8 drops of H2SO4, and then gradually H2S°4'
enough HF1 to dissolve it. Evaporate to dryness (under a hood,
of course), and heat to redness to drive off the H2SO4. Allow
the crucible to cool, add a little Na2CO3, and fuse. Dissolve the
cold fusion in water, add an excess of HC1, evaporate to dryness,
redissolve in HC1 and water, filter from SiO2, and determine the
A12O3, CaO, and MgO as usual. Ignite i gramme of the sand ALA, Cao,

and MgO.

and determine the loss, which will be water and organic matter (if Water
present).

It is well to note that in the presence of A12O3 it is almost
impossible to drive off all the SiO2 by treatment with HF1 and
H2SO4, and the small amount of SiO2 remaining after this treat-
ment must be separated as directed above.

Add together the percentages of water, A12O3, CaO, and MgO,
subtract the sum from 100, and call the remainder SiO2. Sl°«-

281

METHODS FOR THE ANALYSIS

COAL AND COKE.

PROXIMATE ANALYSIS.

A PROXIMATE analysis affords a very rapid and comparatively
simple way of classifying and valuing coal. From the nature
of the material, the determinations cannot be absolute, but infer-
ences may be drawn from the relative proportions of Moisture,
Volatile Combustible Matter, and Ash. Therefore it is essential that
the analysis should be performed in such a way as to obtain the
most concordant results. The series of experiments carried out
by Prof. Heinrichs,* of the Iowa State Geological Survey, show
very clearly that by following a definite course of procedure and
taking a few simple precautions the method may be made suf-
ficiently accurate to accomplish satisfactorily the desired object.
The details, which should in all cases be closely adhered to, are
as follows : Weigh from i to 2 grammes of powdered coal into a
crucible, heat for exactly one hour in an air-bath from 105° to 110°
C, allow the crucible to cool, and weigh it. The loss of weight
divided by the weight of coal taken and the result multiplied by
Moisture. ioo gives the percentage of Moisture in the coal. Weigh from I
Volatile to 2 grammes of the powdered coal into a small platinum crucible,
bustibie heat the crucible with the cover on by means of a Bunsen burner
for three and a half minutes, then, without allowing the crucible

* Chem. News, xviii. 53.
282

ANALYSIS OF THE ASH OF COALS. 283

to cool, heat it for three and a half minutes more at the highest
temperature obtainable by means of a gas blast-lamp. Cool and
weigh. Divide the loss of weight by the amount of material used,
multiply by 100, subtract the percentage of Moisture ', and the
remainder is the percentage of Volatile Combustible Matter. This
determination should always be made on a fresh portion of coal, Fresh p°r-

tion to be

and never on the portion used for the determination of Moisture. used.

After weighing the crucible for the determination of Volatile
Combustible Matter as above, place it over a light in the position
shown in Fig. 12 or Fig. 13, page 22, and burn off the carbon.
This operation, which is liable to be tedious, may be hastened by
breaking up and stirring the mass from time to time with a
platinum rod or a piece of stiff wire. It is necessary to avoid pro-
ducing too strong a draft in the crucible, as by this means par- Precautions

in burning

tides of the ash may be carried out and a fictitious value given to off car.
the coal or coke by the apparent increase of Fixed Carbon and
corresponding decrease of Ash. When no particles of carbon are
apparent in the ash, allow the crucible to cool, and weigh it.
The difference between this weight and the last, divided by the
weight of coal taken, and multipled by 100, gives the percentage
of Fixed Carbon. - ^n

The difference between the sum of the percentages of Water,
Volatile Combustible Matter, and Fixed Carbon and 100 is the per-
centage of Ash. The sum of the percentages of Fixed Carbon and Ash.
Ash is the percentage of Coke which the coal will yield. The Coke-
appearance of the coke before burning off the Fixed Carbon, its
hardness, etc., are often valuable indications of the coking qualities
of the coal, and should be noted. The appearance, color, etc., of
the Ash should likewise be noted.

ANALYSIS OF THE ASH.

The ash may be analyzed by the method given for the analysis
of the Insoluble Silicious Matter in Iron Ores, page 239.

284

ANALYSIS OF COAL AND COKE.

DETERMINATION OF SULPHUR.

Fusion with Weigh out I gramme of the finely-ground coal or coke, and

Na2CO3

and mix it thoroughly, by grinding in a large agate or porcelain mor-

tar, with 10 grammes of dry Na2CO3 and 6 grammes of KNO3.
During the mixing it is well to have the mortar on a large sheet
of white glazed paper, to catch any particles that may be thrown
from it. Transfer the mixture to a large platinum crucible, clean
the mortar by grinding a little Na2CO3 in it, transfer this and any
particles that may be on the paper to the crucible, cover the
latter with a lid, and place it on a triangle over a Bunsen burner.
Heat the crucible very carefully, and raise the heat very slowly,
cautiously removing the lid of the crucible from time to time to
see that the fusion does not boil over. It is very necessary that
none of the fused sodium or potassium salts be allowed to get on
the outside of the crucible, for they will certainly absorb sulphuric
or sulphurous acid from the burned gas, and thus vitiate the analy-
sis. When the mass in the crucible is in a tranquil state of fusion,
run it up on the sides of the crucible, allow it to cool, treat it with
hot water, and wash it out into a small clean beaker. Filter from
the insoluble matter, acidulate the filtrate with HC1, and evaporate
to dryness. Redissolve in water with a few drops of HC1, filter,
dilute the filtrate to about 500 c.c., heat to boiling, and add 10-20
c.c. solution of chloride of barium.* Allow the precipitated sulphate

Washing the of barium to settle, decant the clear, supernatant fluid through a

of barium, filter or through a felt on a Gooch crucible, heat the precipitate

with a solution of acetate of ammonium,t transfer it to the filter,

wash well .with hot water, dry, ignite, and weigh as BaSO4, which,

Method of multiplied by .13756, gives the weight of S. The time of the

ingthe operation may often be very much shortened by adding an excess

lon> of ammonia to the acidulated filtrate of the aqueous solution of

the fusion, and boiling the solution while passing through it a

rapid current of carbonic acid gas. This precipitates the silica,

* See page 51. f See page 45.

DETERMINATION OF SULPHUR.

285

alumina, etc., and, after filtering this off, acidulate by HC1, and
precipitate the sulphate of barium as above directed.

A blank determination, using the same amount of Na2CO3, correction
KNO3, and HC1, should always be made with every new lot of reagents,
reagents, and the amount of BaSO4 found, subtracted from the
amount of BaSO4 in every analysis before calculating the amount
of S in the coal or coke.

Besides the method given above, Eschka's* method is very Eschka's
often used. It is essentially as follows : Weigh out I gramme of
the finely-ground sample, and mix it thoroughly in a mortar with
I gramme of calcined magnesia and .5 gramme of dry carbonate
of sodium, transfer the mixture to a crucible, and heat it over a
Bunsen burner, having the crucible inclined in such a way that the
flame may be applied to the bottom of the crucible, so that the heat,
a dull red, shall extend only about one-third up from the bottom.
Stir the mixture every few minutes with a platinum wire until the
carbon is burned off and the ash is a dull yellow. This will gen-
erally require about one hour. Allow the crucible to cool, add to
the mixture about I gramme of nitrate of ammonium, mix it in
thoroughly with a glass rod, place the lid on the crucible, and heat
it cautiously until the nitrate of ammonium is decomposed and
the crucible is raised to a bright red heat. Allow it to cool, treat it
with hot water, and transfer the contents to a beaker. Filter from
the insoluble matter, acidulate the filtrate with HC1, and determine
the S by precipitation as BaSO4 in the usual way.

In reporting the results of a coal analysis the S should Method of
always be reported as a separate matter, and no attempt should [ngThe
be made to distribute it between the Volatile Combustible Matter,
Fixed Carbon, and Ash. The reason for this is obvious when we coal-
consider the conditions in which S exists in coal, and the diffi-
culty which attends any attempt to determine the amount existing
in any one condition.

* Chem. News, xxi. 261.

286 ANALYSIS OF COAL AND COKE.

Condition Sulphur is known to exist in coal in three conditions, — as a

s exists metallic sulphide, such as pyrites ; as sulphate of calcium or
barium ; and as a sulphuretted hydrocarbon. In a proximate
analysis of coal about one-half the sulphur in any pyrites present
and all the sulphur existing as a sulphuretted hydrocarbon are
probably driven off with the Volatile Combustible Matter. The rest
of the sulphur from the pyrites is oxidized and driven off during
the burning of the Fixed Carbon (sulphate of iron being easily
decomposed at a bright red heat) unless the sulphuric acid
formed is taken up by an alkali or alkaline earth.

Determina- The nearest approach we can make to a determination of the

conditions, conditions in which the sulphur exists in any coal is to make a
determination of the total sulphur by fusion, and a determination
of the sulphuric acid in the ash. By subtracting the S found by
the latter determination from the total S the difference may be
taken to represent the amount existing as S (in the form of sul-
phide), and the amount found in the ash as that existing as SO3
(in the form of sulphate). These results will be correct if the
coal contains no carbonates of the alkalies or alkaline earths.

DETERMINATION OF PHOSPHORIC ACID.

Burning off Burn off io grammes of the coal or coke in a crucible, or,

the coal

or coke, as in anthracite coal or coke this is a very tedious operation, burn
it off in a large platinum boat in a tube in a current of oxygen.
A boat 4 inches (102 mm.) long, and wide enough to fit in a tube
y^ of an inch (19 mm.) in diameter, will hold io grammes very
easily, and by its use this amount of coke or anthracite coal may
be burned off in a current of oxygen in about one and a half
hours. Treat the ash with HC1 to dissolve any phosphate of cal-
cium, filter, and wash well with water. Stand the filtrate aside,
dry, ignite, and fuse the insoluble matter with Na2CO3. Dissolve

DETERMINATION OP PHOSPHORIC ACID.

in water, filter from the insoluble matter, acidulate the filtrate with
HC1, and evaporate to dry ness. Redissolve in water and a little
HC1, filter, add this filtrate to the HC1 filtrate from the first treat-
ment of the ash, add a little ferric chloride solution and a slight
excess of ammonia. Acidulate with acetic acid, heat to boiling, boil
for a few minutes, filter, and wash the precipitate once or twice with
boiling water. Dissolve the precipitate in HC1, evaporate nearly
to dryness, add citric acid, magnesia mixture, and ammonium,
and precipitate as directed on page 85. Filter off, ignite, and
weigh the Mg2P2O7 as there directed. Or, after dissolving the
acetate precipitate, as above, in HC1, evaporate down, and pre-
cipitate the P2O5 by molybdate solution, as directed on page 89
et seq.

METHODS FOR THE ANALYSIS

GASES.

THE technical analysis of gases is of growing importance, and
a knowledge of the methods of analysis and of the manipulation
involved is now generally necessary to the iron chemist. For ease
of manipulation, and for the accuracy of the results obtained by
its use, Hempel's form of apparatus is generally to be preferred.

apparatus.

It consists essentially of a burette for holding and measuring the
gas B, Fig. 101 (the modified Winkler's gas-burette), and a pipette,
G, Fig. 101, which holds the reagent. By means of the level-tube
A, filled with water, the gas is forced into the pipette, where it is
brought in contact with the reagent and afterwards returned to the
burette and measured. By the use of a series of these pipettes,
each filled with a separate reagent, the various constituents of the
gas under examination are absorbed and their volumes estimated.

COLLECTING SAMPLES.

Fig. 98 shows a very simple method for taking a sample of gas
for analysis. The porcelain tube A passes through the brick-work
into the flue through which the gas is carried. In the sketch a
portion of the porcelain tube is cut away, to show the loose fila-
ments of asbestos with which the tube is filled to keep dust or
tarry matter from entering the burette. This asbestos must be put

in very loosely, or else it will pack and interfere with the free pas-
288

COLLECTING SAMPLES.

289

sage of the gas. Where the gas, as from a producer, etc., is
constantly examined, it is very convenient to have a valve fitted
permanently to an iron pipe screwed or cemented into the flue,
into which the porcelain tube may be fastened by means of a
rubber or asbestos * stopper. A glass tube of about ^ inch
(6 mm.) diameter is fitted into the outer end of the porcelain tube

FIG. 98.

A, Fig. 98, by means of a rubber or asbestos stopper, and this
glass tube is connected by means of the rubber tube C with the
opening at the lower end of the burette d. If the gas is under Taking the
pressure (as is rarely the case), it is only necessary to open the In™**:*
stopcocks and allow it to pass through the burette until the air
is entirely displaced. Usually, however, it is necessary to draw
the gas through ; and the little india-rubber pump D attached to

* See page 144.
19

290

ANALYSIS OF GASES.

Aspirator
for draw-
ing gas
through
the bu-
rette.

Compress-
ing the
gas in
the bu-
rette.

Other ves-
sels for
collecting
samples.

FIG. 99.

the capillary tube at the upper end of the burette is very useful
for this purpose. It is fitted with a simple valve at each end, so
that by compressing the bulb in the hand its contents are dis-
charged through the outer end while the pressure closes the valve
at the burette end. When the bulb is released it resumes its shape,
the tension closing the outer valve and opening the one towards
the burette, through which the contents of the latter are drawn
into the bulb. A bulb of the usual size will empty a 100 c.c.
burette in about three strokes. In taking a sample of gas, turn
the 3-way stopcock b so that the passage is open through into the
burette, open the stopcock a at the upper end of the burette, and
pump the gas th-rough slowly for five or six minutes. Close the

upper stopcock #, compress the rubber
tube C between the thumb and fingers
of the left hand, and, holding the tube
with the other hand, slide the left hand
towards the burette. This will com-
press the gas in the burette, and by
closing the stopcock b while the tube
C is thus held the gas in the burette
will be under pressure. In closing b,
it must be turned so that the passage is open from d out through
c, as shown in Fig. 99. Remove the burette to the laboratory,
attach the rubber tube C of the level-tube A, Fig. 101, to the end
of the burette, loosen the pinchcock E, and allow the water to
run through until it comes out through the rubber tube on the
end of the stopcock. Close E, and allow the burette and gas to
attain the temperature of the laboratory. Samples of gas for
analysis may also be taken in glass tubes drawn out at the ends
and closed by rubber tubes and pinchcocks or pieces of glass rod.
When the sample is to be taken to a distance, it may often be col-
lected in a metal vessel with conical ends and tubes with well-
ground stopcocks. Glass vessels of the proper shape, holding
from half a litre to one litre, and fitted with glass stopcocks and

METHOD OF FILLING PIPETTES. 2gr

capillary tubes made for this purpose, may be purchased from
dealers in chemical glass-ware. From these vessels or tubes the
gas may be transferred to the burette by attaching to one outlet a Transfer-
tube filled with water and joined to the burette, likewise filled with burette.' "
water, placing the other end of the vessel in water, lowering the
level-tube, and drawing the gas into the burette.

REAGENTS FOR THE PIPETTES.

Blast-furnace gas, producer gas, and, in general, gases made Composition
by drawing or forcing atmospheric air through coal or coke, con-
tain varying amounts of carbon dioxide (CO2), oxygen (O), carbon
monoxide (CO), hydrogen (H), methane, or marsh gas (CH4), and
nitrogen (N). The best absorbents are caustic potassa for CO2, Absorbents,
pyrogallol for O, and cuprous chloride in HC1 for CO. Hydro-
gen is determined by ignition with excess of oxygen over palla-
dium sponge, and marsh gas by ignition in a tube filled with
cupric oxide. The pipettes required, therefore, are a simple pipette
(G, Fig. 100) filled with caustic potassa, 1.27 sp. gr., for absorbing
CO2, which is readily filled by placing in the large tube of the Method of
pipette a small glass tube, which extends down to the bottom of simpfea
the bulb and is connected outside with a small glass funnel by P'Pette-
means of a piece of gum tubing. Pour the caustic potassa in caustic
through the funnel until the large bulb of the pipette and the tube JJJ^T
connecting the two bulbs are filled with the liquid. Draw the
liquid into the capillary tube until it reaches to within a very short
distance of the rubber tube on the end of the capillary, and close
the rubber tube with a piece of glass tubing or a pinchcock, as
shown in the sketch of the composite pipette, Fig. 100.

A composite pipette (Fig. 106) containing pyrogallol for ab- Method 01

filling a

sorbing oxygen is filled as follows : Dissolve 30 grammes of pyro- composite
gallic acid in 75 c.c. of water, attach a funnel to the capillary tube

20/2 ANALYSIS OF GASES.

of the pipette by a piece of rubber tubing, and fill it with the solu-
tion. Attach a piece of rubber tubing to the other tube of the

pipette, and by gentle suction exhaust the
FIG. loo.

air ; this will cause the liquid to run rap-
idly through the capillary tube into the
pipette. Keep the funnel full until the
liquid which is drawn through the large
bulb into the second bulb fills the latter
to an inconvenient extent, then stop the
suction, and very carefully blow the liquid back into the large
bulb. Fill the funnel again, and exhaust the air gently as
before. Repeat this until all the solution of pyrogallic acid has
been drawn in, and then with the same precautions draw in a
solution of caustic potassa, 1.27 sp. gr., until the large bulb and
the tube connecting the large bulb and the second bulb are filled
with the liquid, which is now an alkaline solution of pyrogallate
Pyrogaiioi of potassium. Close the capillary tube as directed for the caustic
potassa pipette, page 291. Insert the small tube and funnel in the
large tube of the composite pipette, as directed on page 291 for
filling the simple pipette, and pour a little water into the last bulb
of the composite pipette. The amount of water poured in should
not be sufficient to fill the third bulb, for the pyrogallol rapidly
absorbs the oxygen of the air in the second bulb, and this contrac-
tion causes the water poured into the last bulb to rise in the third
bulb. Therefore the amount of water should be small enough to
permit small bubbles of air to pass through to supply the contrac-
tion in the second bulb, and large enough to avoid emptying the
third bulb when the gas during an analysis is forced through the
capillary into the large bulb of the pipette. The amount of pyro-
gallate of potassium from 30 grammes of pyrogallic acid is suffi-
Absorbing cient to absorb nearly 1 500 c.c. of pure oxygen, so that a com-
of^yr^ posite pipette filled in this way, and securely sealed by the water
in the third and fourth bulbs, will last for almost an indefinite
number of analyses.

DETAILS OF THE ANALYSIS.

293

Another composite pipette for absorbing carbon monoxide is cuprous
filled, as above described, with a saturated solution of cuprous pipette6
chloride in HC1, i.i sp.gr., and sealed with water. Each pipette Marking

pipettes.

should be distinctly labelled with the name of the reagent, so
that no mistake can be made in using them.

It is worthy of note that the absorption of CO by cuprous Absorption
chloride is purely mechanical, and is never absolutely perfect, so cuprous
that a small amount of CO invariably remains in the gas after

never

treatment in the cuprous chloride pipette. Moreover, whenever Perfect-
a gas absolutely free from CO is treated in a cuprous chloride
pipette (which has been previously used to absorb CO) and re-
turned to the burette, it will be found to have increased in volume,
and subsequent combustion in a palladium tube will yield an
amount of CO2 corresponding to this increase counted as CO.
If this fact is overlooked, the CO left in the gas will be counted as
methane if a determination of this gas is made in the usual course
of the analysis.

A composite pipette filled with bromine-water to absorb Bromine
ethylene (C2H4) is sometimes used, as this gas has been found
in the gases from blast-furnace and producers using bituminous
coal. But the amount of ethylene is very small, and a separate
determination is rarely made, any small amount being absorbed
and determined as CO.

ANALYSIS OF THE SAMPLE.

The burette containing the gas, with the level-tube filled with
water attached, as mentioned on page 290, having attained the
temperature of the laboratory, raise the level-tube and open the
3-way stopcock so that the passage is open for the water to enter
the burette. If the gas is shown to be under a slight pressure, by
raising or lowering the burette bring the water just to the stop-
cock (if the burette is graduated to read 100 c.c. from stopcock to
stopcock, otherwise bring the water to the o mark), and close the

294

ANALYSIS OF GASES.

Reading the
volume of
gas in the
burette.

FIG. 101.

Method of
connect-
ing the
burette
and the
pipette.

stopcock. Then open the upper stopcock for an instant to allow
the gas to assume the pressure of the atmosphere. Now open the
3-way stopcock to allow the water to enter the burette, hold the
level-tube so that the water in the tube and that in the burette are
at the same level, and observe the reading of the burette. It is a
very simple matter in this way to get exactly 100 c.c. of gas, which
very materially simplifies the calculations. Connect the burette

with the pipette containing caus-
tic potassa by means of the capil-
lary connecting-tube, as shown in
Fig. 101. Some little skill is neces-
sary in making this connection ;
the best way to arrange it is as
follows : Attach one end of the
capillary connecting-tube to the
top of the burette by a piece of
gum tubing, wiring it if neces-
sary, then compress between the
thumb and forefinger of one
hand the rubber tube on the
capillary of the pipette for its
entire length above the pinch-
cock (as shown in Fig. 100),
then carefully introduce the end
of the capillary connecting-tube
into the end of the rubber tube,
and release the rubber tube. If
this is carefully done, the walls
of the rubber tube between the
pinchcock and the end of the
capillary will remain in contact,
showing that no air has been
admitted. Force the end of the capillary tube down to the pinch-
cock, and open the latter, allowing it to remain over the capil-

DETERMINATION OF ETHYLENE. 295

lary, as shown in Fig. 102. The apparatus will now be in the
position shown in Fig. 101. Open the upper stopcock of the
burette, and then turn the 3 -way stopcock D carefully to admit
the water from the level-tube into the burette. As the water
enters the burette the gas is forced over into the pipette G.
Allow the water to fill completely the burette B and to enter the
capillary tube F and fill it as far as the rubber connection between
it and the capillary tube of the pipette G. Close the upper stop- Determina-
cock of the burette, place the pinchcock on the rubber tube be- co>2°
tween the capillary connecting-tube and the pipette, and remove
the capillary connecting-tube F from the rubber tube of the
pipette, leaving it attached to the burette. Take the pipette from
the stand and shake it, to promote the absorption of the CO2,
which will require only a minute or two. Replace the pipette,
attach the capillary connecting-tube F as before, remove the
pinchcock, place the level-tube A on the floor, open the upper
stopcock of the burette, and allow the water to run from the
burette B into the level-tube A, drawing the gas from the pipette
G into the burette B. When the caustic potassa solution has run
back so as to fill the large bulb and the capillary of the pipette
almost to the rubber connection, close the upper stopcock of the
burette B quickly, replace the pinchcock on the rubber tube of the
pipette G, detach the capillary connecting-tube F from the pipette,
hold the level-tube A and the burette B together to get the water
on an exact level, and take the reading of the burette. The differ-
ence between this reading and the original reading will be the
number of c.c. of CO2 absorbed ; and if the original reading was
100 c.c., each c.c. absorbed will be one per cent, of CO2 in the
gas. If any other volume of gas was originally used, divide
the number of c.c. absorbed by the number originally used, mul-
tiply this by 100, and the result is the percentage of CO2 in
the gas.

If ethylene is to be determined, pass the gas into the bromine- Determina-

tion of

water pipette, back into the burette, then into the caustic potassa c2H4.

296

ANALYSIS OF GASES.

Determina-
tion of O.

Determina-
tion of
CO.

Determina-
tion of H.

Description
of the
apparatus.

Transfer-
ring a
portion
of the
unab-
sorbed
gas.

pipette to absorb any bromine fumes, finally back into the burette,
and take the reading as before. The contraction is ethylene.

Now pass the gas into the pyrogallol pipette, shake the latter
gently for four or five minutes to promote the absorption of the
oxygen, return the gas to the burette, and note the reading. The
contraction from the last reading is O.

Pass the gas in the same manner into the cuprous chloride
pipette, detach and shake the latter gently at short intervals for
five or six minutes to promote the absorption of the CO, return
the gas to the burette, and take the reading. The contraction
from the last reading is the CO absorbed by cuprous chloride.
To determine the remaining CO and the H, the gas is mixed with
oxygen and burned over spongy palladium. Fig. icy shows the
arrangement of the apparatus. A is the palladium tube, B the
burette, C a pipette filled with water, D a small gas-burner for
heating the palladium tube, and E the gas-pipe attached to the
wood-work of the pipette and connected by a rubber tube with
a supply of gas. Instead of a gas-burner for heating the palla-
dium tube a small brass spirit-lamp may be used, which is fastened

to the pipette-stand by a clamp in such
a position as to bring the flame under
the palladium tube. With any ordinary
furnace or producer gas which con-
tains 50 per cent, and upwards of nitro-
gen, the best plan is to attach an oxy-
gen-cylinder to the top of the burette,
using a capillary tube and rubber con-
nections, and fill the latter with oxygen

gas. With water-gas, or when a supply of oxygen is not available,
it is necessary to transfer a portion of the unabsorbed gas in the
burette to another burette, and then to admit air to the first burette
until it is nearly filled. Of course it makes the calculation a little
more complicated to change the volume of the gas in this way
during the progress of an analysis, but in the case of nearly pure

FIG. 102.

DETERMINATION OF HYDROGEN. 297

water-gas the use of oxygen alone would probably lead to an
explosion, while with other gases, in the absence of a supply of
oxygen, simply filling the burette with air without letting out any
of the gas might not admit enough oxygen to burn the hydrogen.
After transferring a portion of the unabsorbed gas, read the
burette carefully to get the volume of gas taken for combustion,
and then Divide the volume of gas taken for combustion by the total Calculating
volume unabsorbed, and multiply by the amount originally taken for of gas
analysis ; the result is the number of c.c. of the original gas , to
which the amount taken for combustion corresponds.

After admitting air to the burette, which is done by standing
the level-tube on the floor while the burette is on the table,
opening the 3-way stopcock so that the water may run into the
level-tube, and opening the upper stopcock of the burette until the
proper amount of air has been drawn in, take the reading of the
burette with care. Connect the apparatus as shown in Fig. 102,
light the gas-jet D, open the upper stopcock of the burette B,
and by opening very carefully the 3-way stopcock of the burette
cause the gas to pass very slowly into the pipette C. The palla-
dium tube should not be heated to redness, but to a temperature
just below a dark-fed heat. It is very necessary to avoid carrying precautions
over any water into the hot palladium tube, as it would be certain "oa^old7
to crack it, and for this reason it is well to see that the capillary breaki"s

' the pal-
tube above the stopcock of the burette and both capillary ends of ladium

the palladium tube are dry before making the connections. Any
little moisture may be removed by means of a very fine wire
wrapped with thread. As the water from the combustion of the H
in the palladium is liable to condense in the end of the tube near
the pipette, it is always well to warm this gently with the flame
of a small spirit-lamp or a piece of glowing charcoal, so as to drive
all the moisture into the pipette, and thus prevent its being carried
into the hot part of the palladium tube when the gas is returned
into the burette. When the water has risen in the burette just
above the upper stopcock, lower the level-tube and draw the gas

2gS ANALYSIS OF GASES.

back very slowly into the burette. When the water in the pipette
has risen to the usual position in the capillary, replace the pinch-
cock on the rubber connection between the palladium tube and
the capillary tube of the pipette, extinguish the light under the
palladium tube, and, when the latter is cold, close the upper stop-
cock of the burette, detach the apparatus, open the 3-way stop-
cock fully, and take the reading of the burette.

Now, if there were no CO present in the gas before the com-
bustion, the contraction would be due to the condensation of the
H2O formed by the combustion of the H, and, as 2 volumes of H
unite with I volume of O to form H2O, f of the contraction would
be H. In the presence of CO, however, there is an additional con-
traction beyond that caused by the formation of H2O, due to the
fact that 2 volumes of CO uniting with I volume of O form 2
volumes of CO2. By absorbing the CO2 in the caustic potassa
pipette, and then reading the burette, the second contraction is the

Calculating volume of the CO2, which is the volume of the CO. The first con-
co. traction, then, is f of the H -f \ the CO, and the 'second contrac-
tion being the volume of the CO, it may be stated thus :

first contraction = |-H -f- \ second contraction,
or -|H = first contraction — -^ second contraction;

multiplying by |-,

H=f first contraction — -J second contraction.
Divide the number of c.c. of H and CO respectively as found
above by the number of c.c. of the original gas to which the
amount taken for combustion is equivalent, multiply by 100, and
the result is the percentage of H and CO. This percentage of CO
is to be added to the percentage found by absorption in cuprous

Total co. chloride, and the result is the total CO.

Determina- There remain now in the burette only nitrogen and methane.

CH4. The latter can be properly burned only at a red heat in contact
with oxide of copper, forming H2O and CO2. By absorbing the
CO2 in a solution of caustic baryta, standardized by a normal solu-
tion of oxalic acid, and then titrating the caustic baryta, the volume

DETERMINATION OF METHANE.

of CH4 is at once indicated. As the normal solution of oxalic acid
indicates the volume of CH4 at 760 mm. of barometric pressure
and o° C. of temperature, the thermometer and barometer must be
noted, and the correction made according to the table (Table V.).

Dissolve 5.6314 grammes of crystallized oxalic acid in I litre
of water. I c.c. of this solution indicates i c.c. CO2, or I c.c.
CH4, at 760 mm. barometric pressure and o° C. Dissolve 14.0835
grammes of crystallized hydrate of barium in I litre of water.
I c.c. of this solution is equal to about I c.c. of the oxalic acid
solution.

The apparatus for the determination is shown in Fig. 103. It
consists of a porcelain tube, EE, in the combustion-furnace F ; the

FIG. 103.

299

porcelain tube is nearly filled with coarse oxide of copper between
loose plugs of asbestos, or with a roll of oxidized copper wire (see
page 142). The forward end is connected with two absorption-
bottles, G, G, containing caustic baryta solution. These bottles are
of such a size that 25 c.c. will fill them, so that the gas in bubbling

standard

acid and

caustic

baryta.

3°°

ANALYSIS OF GASES.

through forces a little of the solution up into the bulb-tube, thus
prolonging the contact. If they are a little too large, the solu-
tion of caustic baryta may be diluted, after it is measured in from
the pipette, with a little distilled water to bring it to the proper
Description volume. A is a cylinder containing oxygen under pressure, or,

of the ap-
paratus, if this is not available, a couple of bottles for forcing air through

the apparatus may be substituted (such as those shown in Fig.
57, page 134). The cylinder and the burette B are connected, as
shown in the sketch (Fig. 103), by means of capillary tubes with the
bottle C, containing caustic potassa, 1.27 sp. gr. The bottle C is
connected with the bottle D, containing H2SO4, and from D a
capillary tube passes to the rubber stopper in the end of the por-
Description celain tube EE. Start a current of oxygen or air through the

of the

process. apparatus (before attaching the absorption-bottles G, G), light the
burners of the furnace, and raise the temperature gradually until
the tube is red-hot. Continue the passage of the oxygen until a
bottle containing a solution of caustic baryta attached to the end
of the tube shows that no CO2 is given off. Measure out 25 c.c.
of the caustic baryta solution into each of the bottles G, G, and
attach them as shown in Fig. 103, open the upper stopcock of the
burette B, and by means of the 3-way stopcock let water into the
burette from the level-tube, so that the gas from the burette is
made to bubble very slowly into the bottle C. About three or
four bubbles should pass into C from the oxygen cylinder to one
from the burette. When the water completely fills the burette
and the capillary tube in C, close the upper stopcock of the
burette, and continue the passage of the oxygen from A until it
is certain that all the gas has been carried through the porcelain
tube and the absorption-bottles. In the mean time measure out
25 or 50 c.c. of the caustic baryta solution into a porcelain dish,
dilute with water, add a drop of phenolphtalein solution (made by
dissolving phenolphtalein in alcohol), and from a burette run in
the standard solution of oxalic acid until the pink color of the
solution just vanishes. This will give the value of the caustic

DETERMINATION OF NITROGEN. ^OI

baryta solution in terms of the normal oxalic acid solution. When
the combustion is finished, detach the absorption-bottles, wash their
contents into the dish, add a drop of phenolphtalein solution, and
titrate with the oxalic acid solution. The difference between the calculation
value of- 50 c.c. baryta solution and the value of the 50 c.c. from result,
the absorption-bottles, in terms of the oxalic acid solution, is the
number of c.c. of CH4 in the gas burned at 760 mm. barometric
pressure and o° C. Divide this by the number of c.c. burned,
reduced to 760 mm. pressure and o° C., multiply by 100, and the
result is the volume per cent, of CH4. Add together the percent-
ages obtained of CO2 (ethylene, C2H4), O, CO, H, and CH4, sub-
tract the sum from 100, and the remainder is the percentage of N Determina-

, j-rr tionofN.

by difference.

An example will illustrate the method of analysis, thus :

EXAMPLE OF ANALYSIS.

Siemens' Producer Gas.

Volume of gas employed, 99.7 c.c.

KHO pipette ...... 93.5 c.c. Contraction, 6.2 c.c.

Pyrogallol pipette .... 93.3 " " 0.2 "

CuCl " .... 74.0 " " 19.3 " = 19.36

Transferred a portion.
Remaining in pipette . . . 46.8

Admitted air to ..... 98.4

From palladium combustion

^46.8
-^

CO2

O
CO

= 6.21
= 0.20

1.42" CO (total) = 20.78"

H = 11.23"

CH4 = 3-H"

N = 58.44 "

Burned over palladium . . 87.3
First contraction ..... 1 1 . 1
KHO pipette ...... 86.4

Second contraction .... 0.9 " = CO2 = CO , X 100 = 1.42 <f0 CO.

H = % [ii. i] — K[°-9] = 7-i c.c. gX ioo = n.23# H.

Burned residue over oxide of copper and absorbed CO2 in caustic baryta solution.

Thermometer 17° C. Barometer 745 mm. 745«° — I4-4= 73O.6

7 .0086702 X 100 =.86702
3 .0037158 X 10 =.037158
o x i = .000000

6 .0074316 x o.i = .00074316

.90492116
63.24 c.c. X .90492116 = 57.23 c.c. at 760 mm. and o° C.

50 c.c. caustic baryta solution = 48.3 c.c. oxalic acid
After combustion 50 c.c. " " " =-. 46.5 " " "

Therefore CH4 in gas burned = 1.8 "

1.8
and 5— X 100 = 3.14 % CH4.

302

TABLES.

303

TABLE I.

Atomic Weights of the Elements used in this Volume.

Name.

Symbol.

At. Wt.

Name.

Symbol.

At. Wt.

Aluminium

27 O7

Manganese

C C oo

Antimony

1 2O.OO

Molybdenum

JJ-W
06 oo

Arsenic

yc oo

Nickel ...

cS 7O

Barium

M7.OO

14 O7

Bromine. ,

7Q.QC

Oxygen

16 oo

Calcium

4O 08

Phosphorus .

-JQ Q7

Carbon

12. OO

IQ4 8?

Chlorine ........

?C.4C

Potassium ......

-7Q II

Chromium .

C2 14

Silicon

28 4O

Cobalt

<»Q.OO

21 OS

CoDoer

67 40

Sulphur ......

12 06

I. OO7

Tin

IIQ.OO

Iodine

126 85

Titanium ........

48 oo

Iron .

e6 oo

Tungsten

184 oo

Lead

206. Qt;

ci.^7

Magnesium

24 2Q

Zinc

6c 27

304

THE CHEMICAL ANALYSIS OF IRON.

TABLE II.

Table of Factors.

Found.

A1P04 Al

A12O3 Al

I Sb.2O4 Sb

Sb2S3 Sb

Mg2(NH4)2As2O8-f H2O As

Mg2As207 As

As2S3 As

As FeAs2

BaSO4 S

S03

CaSO4 CaO

CaCO3

CaO CaC03

! C02 C

Cr2O3 Cr

CoSO4 Co

CoO

Co CoO

CoO Co

Cu CuO

Cu2S

CuO Cu

Cu2S Cu

Fe203 Fe

Fe Fe304

FeO

PbSO4 Pb

PbO
PbS

Required.

Factor.

O.22l8l

0.78947
0.71390
0.39400
0.48297
0.60931

I-37333
O.I3756
0.34352
0.41193

0.73513

1.78459

0.27273

0.68479

0.38050

0.48370

1.27119

0.78667

1.25240

1.25284

0.79849

0.79818

0.70000

1.38095

1.28571

0.68298

0.73578

0.78879

Log.

9.3459811-10
9.7243168-10

9.8536374-10
9.5954962-10
9.6839202-10
9.7848383-10

0.1377749

9.1384922-10

9-5359520-10

9.6148234-10

9.8663641-10

0.2515385

9-4357329-IO

9-8355574-IO

9.5803547-10

9.6845761-10

0.1042105

9.8957926-10

0.0977431

0.0978956

9.9022695-10

9.9021008-10

9.8450980-10

0.1401779

0.1091430

9.8344080-10

9.8667480-10

9.8969614-10

TABLES.

TABLE II.— Continued.

305

Found.

Mg2P207 P

MgO
MgC03

Mn3O4 Mn

MnO

Mn2P2O7 Mn

MnO
MnS Mn

MnO
(NH4)3nMo03P04 P

NiO Ni

Ni2S Ni

K2PtCl6 KC1

K2O

KC1 ^ ....... i .... K2CO3

Nad .^ Na2O

Na2C03

Si02 Si

S FeS2

SnO2 Sn

TiO2 Ti

V205 V

W08 W

ZnO Zn

Required.

Factor.

0.27836
0.63788
0.36212
0.75760
0.72052
0.93013
0.38741
0.500II

0-63I75
0-81553
0.01630

0.03735
0.78581
0.78549
0.30696

0.19395
0.92690

0.53077

0.90684
0.47020
I.87336
0.78808
0.60000
0.56222
0.79310
0.80313

Log.

9.4446068-10

9.8047390-10

9.5588525-10

9.8794400-10

9.8576460-10

9.9685437-10

9.5881708-10

9.6990655-10

9.8005453-10

9.9114399-10

8.2121876-10

8.5722906-10

9.8953176-10

9.8951407-10

9.4870818-10

9.2876898-10

9.9670329-10

9.7249064-10

9-9575307-IO

9.6722826-10

0.2726212

9.8965703-10

9.7781513-10

9.7499063-10

9.8993279-10

9.9047858-10

306

THE CHEMICAL ANALYSIS OF IRON.

TABLE III.

Percentages of P and P2O5 for each Milligramme of Mg-2P2O7 when 1O
Grammes of the Sample are used.

Wt. of
Mg2P207.

P205.

Wt. of
Mg2P207.

P205.

Wt. of
Mg2P207.

P. P205.

Wt of
Mg2P207.

P205.

0.003

0.006

0.073

o.i 66

0.142

0.326

0.212

0.486

O.OO5

0.013

0.075

0.173

0.145

0.332

0.215

0.492

O.OO8

0.019

0.078

0.179

0.148

o-339

0.218

0.499

O.OII

0.026

0.081

0.185

0.151

o-345

O.22I

0.505

O.OI4

0.032

0.084

0.192

0.154

o-352

O.223

0.512

O.OI7

0.038

0.086

0.198

0.156

0-358

0.226

0.518

0.019

0.045

0.089

0.204

0.159

0.364

O.229

0.524

O.O22

0.051

0.092

O.2II

0.162

0.371

0.232

0.531

O.O25

0.057

0.095

0.217

0.165

o-377

0.235 0.537

O.O28

0.064

0.098

0.224

0.167

0.384

0.237 0-544

0.031

0.070

O.I 01

0.230

0.170

0.390

0.240

0-55°

°-°33

0.077

0.103

0.237

0.173

0.396

0.243

o-556

0.036

0.083

0.106

0.243

0.176

0.403

0.246

0-563

0.039

0.089

0.109

0.249

0.179

0.409

0.248

0.569

0.042

0.096

O.II2

0.256

0.181

0.416

0.251

0.576

0.045

O.IO2

O.II4 O.262

0.184

0.422

0.254

0.582

0.047

O.IO8

O.II7

0.269

0.187

0.428

0.257

0.588

0.050

O.II5

O.I 2O

0.275

0.190

0-434

0.259

o-595

°-°53

O.I2I

0.123

0.281

0.193

0.441

0.262

0.601

0.056
0.059

0.128
0.134

45
46

0.126

0.128

0.287
0.294

70
7i

0.195
0.198

0.448
0-454

95
96

0.265
0.268

0.607
0.614

22
23

0.061
0.064

O.I4I
0.147

47
48

0.131
0.134

0.300
0.307

72
73

0.201

0.2O4

0.460
0.467

97
98

0.271

0.274

0.620
0.627 '

0.067

0-153

0.137

0-3I3

0.2O7

0-473

0.276

0-633

0.070

O.I59

0.139

0.319 j

O.2O9

0-479

100

0.278

0.638

TABLES.

307

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308

7 HE CHEMICAL ANALYSIS OF IRON.

TABLE V.

Table for Reducing Volumes of Gases to the Normal State.
BY PROFESSOR DR. LEO LIEBERMANN.

(From Winkler's "Technical Gas Analysis.")

Instructions for Use.

Suppose the volume of a gas to have been found =26.2 c.c. at 742 mm. barometric pressure,
1 8° C. temperature, saturated with moisture. In order to reduce it to the normal state (760 mm.,
o° C., dry), we proceed as follows:

1st. Look out the degree 18 (columns I and 4), and deduct the tension of aqueous vapor given,
= 15.3 mm., from the observed pressure, = 742.0:

742.0—15.3 = 726.7 mm.

2d. Now find the volume which I vol. of the gas would have at the pressure of 726.7 mm.
by looking out seriatim the figures 7, 2, 6, and 7 in column 2 at the temperature 1 8°, and placing
the numerical values, to be found opposite those figures, in the same column, multiplying them
seriatim by 100, 10, i, o.i ; whereupon they are added up, thus:

0.0086408 X IO° =0.86408
0.0024688% Io =0.024688

6 0.0074064 X

7 0.0085408 X

i = 0.0074064
o. i = 0.00086408

0.89703848

3d. The corrected volume of a cubic centimetre is lastly multiplied by the number of the c.c.
previously found ; that is, in the present case,

0.89703848X26.2 = 23.502 c.c.

Tempera-
ture ° C.

Pressure
in millims.
mercury.

Volume at o°
and 760 mm.

Tension of aq. !
vapor in millim. i
of mercury
for ° C.

Tempera-
ture ° C.

Pressure
in millims.
mercury.

Volume at o°
and 760 mm.

Tension of aq.
vapor in millim.
of mercury
for ° C.

0.0013157

0.0078946

0.0026315

O.OO92IO4

0.0039473

0.0105262

0.0052631

O.OII842O

0.0065789

o° = 4-5

TABLES.

TABLE V. — Continued.

309

Tempera-
ture ° C.

Pressure
in millims.
mercury.

Volume at o°
and 760 mm.

Tension of aq.
vapor in millim.
of mercury
for ° C.

Tempera-
ture ° C.

Pressure
in millims.
mercury.

Volume at o°
and 760 mm.

Tension of aq.
vapor in millim.
of mercury
for ° C.

0.0013109

0.0012965

0.0026219

0.0025930

0.0039328

0.0038895

0.0052438

0.0051860

0.0065548

I° = 4.9

0.0064825

4° == 6.0

0.0078657

0.0077790

0.0091767

0.0090755

0.0104876

O.OIO372O

0.0117986

0.0116685

0.0013061

0.0012916

0.0026123

0.0025833

0.0039184

0.0038750

0.0052246

0.0051667

0.0065307

2° = 5-2

0.0064584

5° = 6.5

0.0078369

0.007750!

0.0091430

0.0090418

0.0104492

0-0103335

0-0"7553

0.0116252

0.0013013

0.0012868

3 -

0.0026026

0.0025737

0.0039039

0.0038606

0.0052053

0.0051474

0.0065066

3° = 5-6

0.0064343

6° == 6.9

0.0078079

0.0077212

0.0091093

0.0090080

O.OIO4IO6

0.0102949

0.0117119

0.0145818

3io

THE CHEMICAL ANALYSIS OF IRON.

TABLE V.— Continued.

Tempera-
ture o C.

Pressure
in millims.
mercury.

Volume at o°
and 760 mm.

Tension of aq.
vapor in millim.
of mercury
for ° C.

Tempera-
ture ° C.

Pressure
in millims.
mercury.

Volume at o°
and 760 mm.

Tension of aq.
vapor in millim.
of mercury
for ° C.

0.0012828

0.0012692

0.0025656

0.0025384

0.0038484

0.0038076

0.0051312

0.0050768

0.0064140

7° = 7-4

0.0063460

10° = 9.1

0.0076968

0.0076152

0.0089796

0.0088844

0.0102624

0.0101536

0.0115452

0.0114228

0.0012783

0.0012648

0.0025566

0.0025296

0.0038349

0.0037944

0.0051132

0.0050592

0.0063915

8° = 8.0

0.0063240

11° = 9.7

0.0076698

0.0075888

0.0089481

0.0088536

0.0102264

O.OIOII84

0.0115047

0.0113832

0.0012737

0.0012603

0.0025474

O.OO252O6

0.0038211

0.0037809

0.0050948

0.0050412

0.0063685

9° = 8.5

0.0063015

12° = IO.4

0.0076422

0.0075618

0.0089159

O.OO8822I

0.0101896

O.OIOO824

0.0114633

0.0113427

TABLES.

TABLE V.— Continued.

Tempera-
ture ° C.

Pressure
in millims.
mercury.

Volume at o°
and 760 mm.

Tension of aq.
vapor in millim.
of mercury
for o C.

Tempera-
ture ° C.

Pressure
in millims.
mercury.

Volume at o°
and 760 mm.

Tension of aq.
vapor in millim.
of mercury
for o C.

0.0012559

O.OOI2429

0.0025II8

0.0024858

0.0037677

0.0037287

0.0050236

0.0049716

0.0062795

13° = 11. 1

0.0062145

16° = 13.5

°-0°75354

0.0074574

0.0087913

0.0087003

0.0100472

0.0099432

0.0113031

o.oi 11861

0.0012516

0.0012,386

0.0025032

0.0024772

0.0037548

0.0037158

0.0050064

0.0049544

0.0062580

14° = 11.9

0.0061930

1 7° = 14.4

,0.0075096

O.OO743I6

0.0087612

O.OO867O2

0.0100128

0.0099088

0.0112644

O.OIII474

0.0012472

0.0012344

0.0024944

0.0024688

0.0037416

0.0037032

0.0049888

0.0049376

0.0062360

15° = 12.7

O.OO6I72O

180 = 15.3

0.0074832

0.0074064

0.0087304

0.0086408

0.0099776

0.0098752

0.0112248

O.OIII096

312

THE CHEMICAL ANALYSIS OF IRON.

TABLE V.— Continued.

Tempera-
ture ° C.

Pressure
in millims.
mercury.

Volume at o°
and 760 mm.

Tension of aq.
vapor in millim.
of mercury
for ° C.

Tempera-
ture ° C.

Pressure
in millims.
mercury.

Volume at o°
and 760 mm.

Tension of aq.
vapor in millim.
of mercury
for ° C.

O.OOI23OI

O.OOI2I76

0.0024602

0.0024352

0.0036903

0.0036528

0.0049204

0.0048704

0.0061505

I9° = I6.3

0.006o88o

22° = 19.6

0.0073806

6 '

0.0073056

O.OO86lO7

0.0085232

0.0098408

0.0097408

O.OII0709

0.0109584

O.OOI2259

O.OOI-2I35

0.0024518

0.0024270

0.0036777

0.0036405

0.0049036

0.0048540

0.0061295

2O° = 17.4

0.0060675

23° = 2O.9

0-0073554

0.0072810

0.0085813

0.0084945

0.0098122

0.0097080

O.OIIO33I

0.0109215

0.0012218

O.OOI2O94

0.0024436

0.0024188

0.0036654

0.0036282

0.0048872

0.0048376

0.0061090

21° =18.5

0.0060470

24° = 22.2

0.0073308

0.0072564

0.0085526

0.0084658

0.0097744

0.0096752

0.0109962

0.0108846

TABLES.

TABLE V.— Continued.

313

Tempera-
ture o C.

Pressure
in millims.
mercury.

Volume at o°
and 760 mm.

Tension of aq.
vapor in millim.
of mercury
for ° C.

Tempera-
ture o C.

Pressure
in millims.
mercury.

Volume at o°
and 760 mm.

Tension of aq.
vapor in millim.
of mercury
for ° C.

O.OOI2O54

0.0011933

0.0024108

0.0023866

0.0036162

0.0035799

0.0048216

0.0047732

0.0060270

25° = 23.5

0.0059665

28° = 28. 1

0.0072324

0.0071598

0.0084378

0.0083531

0.0096432

0.0095464

0.0108486

0.0107397

O.OOI20I3

0.0011894

O.OO24O26

0.0023788

0.0036039

0.0035682

0.0048052

0.0047576

0.0060065

26° =r 25.0

0.0059470

29° = 29.8

0.0072078

0.0071364

0.0084091

0.0083258

0.0096104

0.0095152

O.OI08II7

0.0107046

0.0011973

3°

O.OOII855

0.0023946

0.0023710

0.0035919

0.0035565

0.0047892

0.0047420

0.0059865

270 = 26.5

0.0059275

30° = 31.6

0.0071838

0.0071130

0.0083811

0.0082985

0.0095784

0.0094840

0.0107757

0.0106695

APPENDIX.

Determination of Nickel and Aluminium in Steel.

AN admirable and rapid method for the determination of nickel or
aluminium in steel has been worked out by Mr. George H. Chase of the
Midvale Steel Company, Philadelphia, from the separation mentioned by
J. W. Rothe.* This is based on the fact that ether will take ferric chloride
from its solution in dilute hydrochloric acid, leaving aluminium, nickel,
and copper chlorides in the hydrochloric acid solution.

The details as communicated to me by Mr. Chase are as follows :

Determination of Nickel,

Dissolve 2 grammes of steel in dilute hydrochloric acid (i.i sp. gr.),
add sufficient nitric acid to oxidize the iron, and evaporate to dryness.
Redissolve in hydrochloric acid and evaporate until ferric chloride begins
to separate. Add hydrochloric acid, i.i sp. gr., to redissolve any basic
salt, and transfer the solution to a 250 c.c. separatory funnel provided with
a glass stop-cock and closed at the top with a ground glass stopper.

As hydrochloric acid of i.i sp. gr. only is used in this method it is
best to have a wash-bottle filled with it. Wash the solution out of the
beaker with hydrochloric acid, being careful that the entire volume of solu-
tion and washings in the funnel shall not exceed 50 c.c. Pour 40 c.c. of
C. P. ether into the funnel, insert the glass stopper, and shake vigorously
for eight minutes. The ether gradually removes the ferric chloride from
the solution and finally appears as an emerald-green solution floating on
top of the aqueous solution of the other chlorides. Allow the funnel to
stand for a few minutes and then run the lower solution which contains
the nickel, copper, and aluminium chlorides into another similar separatory
funnel into which 40 c.c. of ether has been previously placed. Close the
stop-cock and wash the glass stopper with a little hydrochloric acid, allow-
ing it to run into the first funnel, and wash the funnel itself with a little

* Miltheilungen aus den Koniglich. Tech. Versachs anstalten zu Berlin, 1892, part iii.

APPENDIX.

more acid. Allow this to run into the second funnel and repeat the wash-
ing. When the second washing has run into the second funnel pour the
green etherial solution into a bottle and reserve it to distil and recover the
ether. Shake the second funnel for eight or ten minutes to remove the
last of the ferric chloride and separate and wash as before. Boil the sepa-
rated liquid which contains the nickel, copper, and aluminium chlorides, and
the hydrochloric acid to expel a trace of ether, add an excess of ammonia
to precipitate any iron or alumina that may be present and boil. Filter,
wash, redissolve in hydrochloric acid, reprecipitate by ammonia, and filter.
Add the two filtrates together, acidulate strongly with hydrochloric acid,
and pass sulphuretted hydrogen to get rid of the copper. Filter, nearly
neutralize the filtrate with ammonia, add 5 to 10 grammes of ammonium
or sodium acetate, and precipitate the nickel by sulphuretted hydrogen.
Determine the nickel as directed on page 1 86. Or evaporate the liquid
separated from the etherial solutions to low bulk, separate the copper by
sulphuretted hydrogen, evaporate the nickel solution with an excess of
sulphuric acid, and separate the nickel by the battery.

Mr. Chase prefers to run the liquid from the second treatment with
ether into 5 to 10 grammes of ammonium chloride dissolved in 100 c.c.
strong ammonia, and after heating to boiling to filter off the precipitated
ferric hydrate, then to boil off all the ammonia, filter if necessary, add
10 grammes of sodium or ammonium acetate, and precipitate the nickel
by sulphuretted hydrogen at a temperature of about 80° C. He sub-
tracts the cuprous sulphide, previously determined, from the sulphides
thus obtained.

A determination of nickel can be made by this method in about two
hours, and the results are very accurate.

Determination of Aluminium.

Proceed as in the determination of nickel until the liquid from the
treatments with ether is obtained. Evaporate to dryness, redissolve in a
little hydrochloric acid, filter, add sodium ammonium phosphate and
sodium hyposulphite, and precipitate by sodium acetate, determining the
aluminium as on page 192.

INDEX.

Absorption apparatus for CO2 in carbon

determinations 145

precautions in weighing .... 146

Acetic acid, reagent 40

Acids and halogens 38

Air, compressed, for use in carbon deter-
mination in iron and steel 156

Air-bath 19

Air-blast with Richards's injector .... 23

Alkalies, determination of, in clay . . 272, 273

determination of, in iron ores .... 255

Alkaline earths, salts of 50

salts 44

Allen, determination of nitrogen in iron

and steel .... 2OI

Alumina and ferric oxide, separation of . 248

by caustic potassa or soda . . . 249

by hyposulphite of sodium . . . 250

by sulphide of ammonium . . . 248
by volatilization of the iron in a
current of HC1 after reduction

by H 250

Aluminium, separation of, from chro-
mium 188, 189

Aluminium and chromium, determination

of, in iron and steel 187, 191, 192

Ammonia, jeagent 44

Ammonium, acetate of, reagent 45

bisulphite of, reagent 44

chloride of, reagent 45

fluoride of, reagent 45

nitrate of, reagent 45

oxalate of, reagent 45

salts, decomposition of, by HNO3 . . 256

sulphide of, reagent 44

Antimony, determination of, in iron and

steel 196

Apparatus 1 1

general laboratory 19

Arsenic, determination of, as As2S8 ... 196

as Mg2As2O7 196

by distillation 195

in iron and steel 195

Arsenic and antimony, separation of, from

copper and lead 253

Arsenic, copper, antimony, and lead, deter-
mination of, in iron ores 253

Asbestos stoppers 144

Babbitt, use of red lead in Deshays's method
for determination of manganese in iron

and steel 125

Balances 36

Barba, asbestos for settling carbonaceous

matter in solutions of steel . . . . 151

determination of chromium in steel . 194

member of sub committee on methods 95

Barium, acetate of, reagent 51

carbonate of, reagent 50

chloride of, reagent 51

hydrate of, reagent 51

Baryta, caustic, reagent 51

caustic, standard solution of, for de-
termination of methane 299

Berzelius, determination of carbon in iron

and steel 129, 130

determination of sulphur in iron and

steel . ,. 62

Binks, determination of carbon in iron and

steel 130

Boat of platinum-foil for determination of

carbon in iron and steel 159

Britton, permanent standards for color-car-
bon method 174

3'5

INDEX.

Bromine, reagent 41

Bromine-water for absorbing ethylene . . 293

Bunsen burners 22

chimneys for 22

Bunsen, determination of MnO2 in iron

ores 235

Bunsen's method of rapid filtration ... 24

Burette, form of, without glass stopcock . 213

Jones's 211

Calcium, carbonate of, reagent 52

chloride of, reagent 52

Camera, for use in color-carbon method . 173

Caps for reagent bottles 32

Carbon, determination of, in iron and steel 129
in carbonaceous matter, determination

of, in iron ores 259

Carbon, combined, determination of, in iron

and steel by color method . . 167
determination of, in white cast

iron and pig-iron .... 176

by direct method 167

by indirect method .... 167
limitations of color method . . 167
Carbon, total, determination of, in iron and

steel 129

by combustion with chromate of

lead and chlorate of potassium 132
by combustion with oxide of cop-
per in a current of oxygen . . 135
by combustion with potassium bi-

sulphate 135

by direct combustion in a current

of oxygen 131

by solution and oxidation of the
borings by sulphuric, chromic,
and phosphoric acids, the vol-
ume of CO2 being measured . 136
by solution and oxidation of the
borings by sulphuric, chromic,
and phosphoric acids, the CO2

being weighed 140

by solution in chloride of copper,

and combustion of residue . . 162
by solution in double chloride of
copper and ammonium, and
weighing or combustion of res-
idue 148

Carbon, total, determination of, by solution
in chloride of copper and chlo-
ride of potassium, and combus-
tion of residue 161

by solution in dilute hydrochloric
acid in an electric current, and
combustion of residue .... 165
by solution in iodine or bromine,

and combustion of residue . . 162
by solution on fused chloride of ?
silver, and combustion of resi-
due 163

by solution in sulphate of copper,
and combustion of residue by

CrO3 and H2SO4 164

by solution in sulphate of copper,
and combustion of residue in a

current of oxygen 163

by volatilization in a current of Cl,

and combustion of residue . . 142
by volatilization in a current of
HC1, and combustion of resi-
due 148

Carbonic acid gas, absorbent for .... 291
apparatus for generating .... 42
determination of, in gases . . . 295
determination of, in iron ores . . 257
purifying and drying apparatus
for, in carbon determinations .

144, 154, 156

Carbonic oxide gas, absorbent for . . . . 291
absorption of, by cuprous chloride 293
determination of, in gases . . . 296
Carnot, determination of aluminium in iron

and steel 192

Chimneys for Bunsen burners 22

Chlorine, reagent 41

Chrome iron ore, analysis of 263

Chromium, determination of, in iron and

steel 190

determination of, in iron ores .... 262
separation of, from aluminium . 188, 189
volumetric method for determination

of, in iron and steel 193

Chromium and aluminium, determination

of, in iron and steel 187

separation of, from P2O5 .... 189
Cinder, mill and tap, analysis of .... 278

INDEX.

317

Citric acid, reagent 40

Clay, methods for the analysis of .... 271

Coal, analysis of the ash of 283

determination of sulphur in .... 284

proximate analysis of 282

Coal and-coke, methods for the analysis of 282

Cobalt, determination of, as CoSO4 . . 185

determination of, by electrolysis ... 1 86
Cobalt and nickel, determination of, in iron

and steel 184

Coke, determination of sulphur in .... 284
Combined water, determination of, in iron

ores 259

Comparison-tubes for color carbon method 172

Cone, Gooch's perforated 27

Copper, determination of, as CuO .... 184

as Cu2S 183

by electrolysis 182

by precipitation by hyposulphite

of sodium 183

anhydrous sulphate of, reagent ... 53

metallic, reagent 52

oxide of, reagent 54

sulphate of, reagent 53

Copper and ammonium, double chloride of,

reagent 54

and potassium, double chloride of, re-
agent 54

lead, arsenic, and antimony, determina-
tion of, in iron ores 253

Counterpoised filters 27

Craig, determination of sulphur in iron and

steel 65

Crucible, Gooch's perforated 26

platinum 32

Crucible-tongs, forms of 35

Cupric chloride, reagent 53

Cuprous chloride, anhydrous, reagent . . 53
for absorbing carbon monoxide

291, 293

Deshays, determination of manganese in

iron and steel 124

Desiccators 32

Deville, determination of carbon in iron

and steel 130

Dexter, method of separation for Cr and Al 188

Dishes, platinum 34

Distilled water 37

apparatus for making 38

Drill-press 15

Drill-press for holding half pig of iron . . 15

Drill-press and balance 16

Drown, determination of silicon in iron

and steel 73

determination of sulphur in iron and

steel 64

determination of titanium in iron . . 180
member of sub-committee on standard

methods 95

Drying and purifying apparatus for CO2 in

carbon determinations .... 144, 154, 156
Dubois, Mixer and, determination of iron

in iron ores 218

Dudley, chairman sub- committee on stand-
ard methods 95

Eggertz, determination of carbon in iron

and steel 130

determination of combined carbon in

iron and steel 167

determination of phosphorus in iron

and steel 92

Elliott, determination of sulphur in iron

and steel 68

Eschka, determination of sulphur in coal

and coke 285

Ethylene, absorbent for 293

determination of, in gases 295

Factor weights 37

Feather for removing precipitates .... 31
Ferric chloride, solution of, for standard-
izing solutions of permanganate and bi-
chromate 219

Ferrous oxide, determination of, in iron ores 223

sulphate, reagent 55

Filters, apparatus for washing ." 29

ashless 29

Filtering-tubes for carbon determinations in

iron and steel 157

Filter-paper 28

Filter-pumps 23

Filtration, Bunsen's method of 24

Fire-sand, methods for analysis of . . . . 281

INDEX.

Forceps for use in carbon determinations in

iron and steel 154

Ford, determination of manganese in iron

and steel 115

rapid method for determination of sili-
con in pig-iron 77

Fresenius, determination of phosphorus in

iron and steel 81

determination of sulphur in iron and

steel 63

Galbraith, volumetric method for determi-
nation of chromium in iron and steel . . 193
Gas, heating, composition of 291

Siemens's producer, example of analy-
sis of 302

Gases, analysis of, by Hempel's apparatus 293

collecting samples of, for analysis . . 288

methods for the analysis of 288

reagents 42

Genth, method of decomposing chrome ores 263

method for the separation of Al and Cr 189
Glass filtering-tube for carbon determina-
tions in iron and steel 157

Gooch, separation of TiO2 and A12O3 . . 231

Gooch's method of filtration 26

perforated crucible and cone .... 26
Graphitic carbon, determination of, in iron

and steel 166

Hempel's apparatus for the analysis of

gases 288

Hogarth, specific-gravity flask 265

Hydrochloric acid, reagent 38

Hydrofluoric acid, apparatus for distilling 39

reagent 39

Hydrogen, combustion of, with spongy pal-
ladium 297

gas, apparatus for generating .... 43
Hydroscopic water, determination of, in

iron ores 206

Igniting precipitates 22

Insoluble silicious matter in iron ores, anal-
ysis of ... 239

Iodine, reagent 41

Iron, determination of metallic, in iron and

steel 204

Iron, total, determination of, in iron ores . 207

Iron, total, in irqn ores, determination of, by

deoxidation by NH4HSO3 216
by deoxidation by SnCLj . . 217
by deoxidation by Zn . . . 208
by standard solution of bi-
chromate of potassium . . 215
by standard solution of per-
manganate of potassium . 209

Iron ores, method of sampling 205

Iron wire, reagent 55

Iron and ammonium, double sulphate of,

reagent 55

Jones's reductor 209

Karsten, determination of graphitic carbon

in iron and s*teel 166

determination of sulphur in iron and

steel 59

Kudernatsch, determination of carbon in

iron and steel 130

Langley, determination of carbon in iron

and steel 130

determination of nitrogen in iron and

steel 201

Lead, determination of, as PbSO4 in iron

ores 253

chromate of, reagent 56

oxide of, dissolved in caustic potassa . 57

peroxide of, reagent 57

Lead, copper, arsenic, and antimony, deter-
mination of, in iron ores 253

Limestone, methods for the analysis of . . 267

occasional constituents of 268

Lundin, determination of arsenic in iron

and steel 195

Magnesia mixture, reagent 58

Manganese, binoxide of, in iron ores . . . 235
determination of, by Bunsen's

method 236

by ferrous sulphate method . 237

determination of, as Mn3O4 113

as MnS 114

as Mn2P2O7 112

in iron and steel, by acetate

method 109

INDEX.

319

Manganese, determination of, in iron and

steel, by Deshays's method . . 124

by Ford's method 115

by HNO3 and KC1O3 method . 115

by Volhard's method 118

by Williams' s method ..... 1 20
in presence of much silicon

(Wood's method) 117

rapid methods 118

remarks on the use of acetate

method H4

in iron ores 233

by Volhard's method 234

by Pattinson's method 234

in pig-iron, spiegel, and ferro-manga-

nese, by Ford's method 118

in spiegel and ferro-manganese ... 123

by Pattinson's method 125

by Williams' s method 123

determination of, in steel, by the color

method 126

in presence of much silicon (by Ford's

method) , .' 117

Marguerite's method for determination of

iron 209

Matthewman, determination of sulphur in

pig-iron 66

McCreath, determination of carbon in iron

and steel . . . . - 130

Measuring-glasses for reagents 31

Mercuric oxide, reagent 56

Mercurous nitrate, reagent 56

Metals and metallic salts, reagents .... 52
Methane, determination of, in gases . . . 298
Microcosmic salt, quantity in the determi-
mination of MgO in lime-
stones 268

reagent 46

Mixer and Dubois, determination of iron in

iron ores 218

Molybdate solution, reagent 58, 99

Morrell, determination of sulphur in iron

and steel 62

Mortar, agate, with Stow flexible shaft . . 13
agate, White's arrangement to use

with power 14

hardened steel, for spiegel 17

Mortar and pestle, steel, for crushing ores 12

Nichols, details of rapid method for deter-
mination of phosphorus in iron and steel 108
Nickel, determination of, as Ni2S or NiO . 186

separation of, from cobalt 185

Nickel and cobalt, determination of, by

electrolysis 186

determination of, in iron and steel 184
separation of, from copper ... 184
Nickel, cobalt, zinc, and manganese, deter-
mination of, in iron ores 251

Nickel steel, analysis of 186

Nitric acid, reagent 39

Nitrogen, determination of, in iron and

steel 201

Oxalate of ammonium, quantity required
in the determination of CaO in lime-
stones 267

Oxalic acid, reagent 40

standard solution of, for determi-
nation of methane 299

Oxide of copper plugs, preparation of . . 142

Oxygen, determination of, in gases . . . 296

gas, absorbent for 291

reagent 43

Pan, aluminium, for weighing samples . . 36
Pearse, determination of carbon in iron and

steel 130

Penny's method for determination of iron . 215
Perforated boat and holder for filtering
carbonaceous residues from iron and

steel 151, 152

Permanent standards for color carbon de-
termination 174

Permanganate of potassium solution,

methods of standardizing 218-222
standard solution of, for determi-
nation of iron 209

Peters, determination of manganese in steel

by color method 126

Phillips, determination of sulphur in pig-
iron 66

Phosphoric acid, determination of, in coal

and coke 286

in iron ores 229

in limestone 269

in slags 279

320

INDEX.

Phosphorus, determination of, in iron and

steel 81

by direct weighing of phospho-

molybdate 1 08

by the acetate method .... 81
by the acetate method, precau-
tions necessary 84

by the combination method . . 93
by the molybdate method . . 89
by the molybdate method, pre-
cautions necessary .... 92
by volumetric method (method
of the sub-committee on
methods of the International
Steel Standards Committee) 95
by rapid methods . . . -95
when titanium is present 86, 94

asMg2P207 85

as Mg2P2O7 with previous pre-
cipitation as phospho-molyb-

date 91

as phospho-molybdate of am-
monium 92

separation of, from arsenic .... 84, 92

Phospho-titanate, insoluble 179

Pichard, determination of manganese in

steel by color method 126

Pipette, Hempel's composite, method of

filling 291

Hempel's simple, method of filling 291

Plate, chilled-iron, and muller 12

Platinic chloride solution, reagent .... 57

Platinum apparatus 32

combustion-tube for carbon determi-
nations in iron and steel 154

crucibles, method of cleaning ... 33
filtering-tube for carbon determina-
tions in iron and steel 157

" Policemen'' for removing precipitates . 31

Potassa, caustic, reagent ........ 47

Potassa and soda, separation of 256

Potassium, bichromate of, reagent .... 48

bisulphate of, reagent 49

chlorate of, reagent 48

ferricyanide of, reagent 50

ferrocyanide of, reagent 50

iodide of, reagent 49

nitrate of, reagent 48

Potassium, nitrite of, reagent 47

permanganate of, reagent 50

sulphide of, reagent 48

Purifying apparatus for oxygen and air . . 144
Pyrogallate of potassium, absorbent power

of 292

Rack for permanent standards in color car-
bon method 175

Rapid evaporations, apparatus for .... 20

Rapid filtration, Bunsen's method of ... 24

Gooch's method of 26

Reagents 37

for determining phosphorus .... 58

for the analysis of gases 291

Reductor, Jones's, for ferric sulphate solu-
tions 209

simple form of 95

Regnault, determination of carbon in iron

and steel 130

Richards injector 23

Richter, determination of carbon in iron

and steel 130

Riley, determination of titanium in pig-
iron 178

Rivot, separation of alumina and ferric

oxide 250

Rubber stoppers 32

Safety-guard tube in CO2 determinations . 145

Sampling iron ores, method of 205

pig-iron, method of 1 6

Sand-bath 19

Shinier, member sub-committee on Stand-
ard methods 95

insolubility of carbide of titanium in

hydrochloric acid 167

Siemens's producer gas, example of analy-
sis of 302

Silica, determination of, in iron ores . 239, 247
Silica, alumina, lime, magnesia, oxide of
manganese, and baryta, determination

of, in iron ores 238

Silicon, determination of, in iron and steel 72

by solution in HNO3 and HC1 . 72

by solution in HNO3 and H2SO4 73

by volatilization in a current of

chlorine gas 73

INDEX.

321

Silicon, determination of, in iron and steel,

rapid method, by Ford 77

Slag, basic, analysis of 279

converter, analysis of 278

decomposed by HC1, analysis of . . 276
not decomposed by HC1, analysis

of 278

refinery, analysis of 278

Slags, methods for the analysis of .... 276
Slags and oxides, determination of, in iron

and steel 78

by solution in iodine ... 79
by volatilization in a current

of chlorine gas 80

Smith, J. L., determination of alkalies in

minerals 273

Soda, caustic, reagent . . . . 46

Soda and potassa, separation of 256

Sodium, acetate of, reagent 47

carbonate of, reagent 46

hyposulphite of, reagent 47

nitrate of, reagent 46

thiosulphate of, reagent 47

Sodium and ammonium, phosphate of, re-
agent 46

Sonnenschein, determination of phosphorus

in iron and steel 89

Spatulas, platinum 34

Specific gravity of iron ores, method of de-
termining 265

Stand for holding absorption apparatus for
CO2 in the determination of carbon in

iron and steel 146

Standard solutions for determination of

iron, proper strength of 222

Standardizing volumetric solutions for de-
termination of iron by ferrous

sulphate 222

by iron wire 221

by solution of ferric chloride . . 219
Stead, determination of combined carbon in

low-carbon steels and iron .... 176
determination of chromium and alu-
minium in iron and steel 191

Stead's chromometer 177

method for low- carbon steels .... 176
Stirring machine for dissolving steel and

iron in carbon determinations .... 149

Sulphate of barium, determination of, in

iron ores 228

Sulphates, soluble, determination of, in iron

ores 228

Sulphur, conditions of, in coal 286

as sulphides, in iron ores 229

determination of, in iron and steel by

evolution as H2S 59

by evolution as H2S, and absorp-
tion by alkaline solution of ni-
trate of lead 59

by evolution as H2S, and absorp-
tion by ammoniacal solution of
sulphate of cadmium .... 62
by evolution as H2S, and absorp-
tion in ammoniacal solution of

nitrate of silver 62

by evolution as H2S and absorp-
tion and oxidation by bromine

and HC1 63

by evolution as H2S and absorp-
tion and oxidation by perman-
ganate of potassium 64

by evolution as H2S and absorp-
tion and oxidation by peroxide

of hydrogen 65

by oxidation and solution ... 65

by rapid method 68

determination of, in coal and coke . . 284
determination of, in pig-iron, special

precautions 66

total, determination of, in iron ores . 226
method of reporting amount of, in

coal 285

Sulphuretted hydrogen gas, apparatus for

generating 43

Sulphuric acid, reagent 39

Sulphurous acid, reagent 41

Svanberg and Struve, phospho-molybdate
reaction 89

Tartaric acid, reagent 40

Tin, determination of, in iron and steel . . 197
Titanic acid, determination of, in clay . . 274
determination of, in iron ores . . 231
interference of P2O5 with precipi-
tation of 179

iron ores containing 229

322

Titanic acid, iron ores containing, analysis
of

separation of from P2O5 ....

tests for, in iron ores

Titan iferous iron ores, method of recog-
nizing

Titanium, determination of, in iron . . .

by precipitation

by volatilization

Triangles and tripods of platinum ....

Tripods

Tungsten, determination of, in iron and steel

in iron ores

rapid method for determination of,
in iron and steel

Uehling, apparatus for delivering different

volumes of HNO3

apparatus for delivering constant vol-
umes of ferrous sulphate solution .
Ullgren, determination of carbon in iron
and steel

Vanadium, determination of, in iron and

steel 200

determination of, in iron ores .... 264
Volhard, determination of manganese in

iron and steel 118

iron ores 234

Washing-bottles, forms of 30

Watch-glasses, balanced 36

INDEX.

244
179

230

178

1 80

198

264

199

170

Water-bath, for determination of hygro-
scopic water in iron ores .... 206
for use in color carbon method and

color manganese method .... 169
Watts, determination of silicon in iron and

steel . 73

Weyl, determination of carbon in iron and

steel 130

Whitfield, apparatus for hastening evapora-
tions 20

Williams, method for determination of

manganese in iron and steel 120

Wohler, determination of carbon in iron

and steel 130

separation of alumina and ferric oxide 250
Wood, modification of color carbon method

for low steels 172

rapid method for determination of

phosphorus in iron and steel . . . 108
use of HF1 in steels high in silicon
and pig-irons, in determination of
manganese 117

Zimmerman, determination of iron in iron

ores 217

Zinc, determination of, in iron ores ... 251

metallic, reagent 57

amalgamated for use in reductor . loo
powdered for reducing molybdic

acid 102

oxide of, in water, reagent 58

THE END.

UNIVERSITY OF CALIFORNIA LIBRARY

THIS BOOK IS DUE ON THE LAST DATE
STAMPED

- SEP

1916

30m-6,'14

YD 04985

G.-UI

/36

18*96

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Full text of "The chemical analysis of iron. A complete account of all the best known methods for the analysis of iron, steel, pig-iron, iron ore, limestone, slag, clay, sand, coal, coke, and furnace and producer gases"

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